bcma: make bcma_core_pci_{up,down}() callable from atomic context

bcma: make bcma_core_pci_{up,down}() callable from atomic context

This patch removes the bcma_core_pci_power_save() call from
the bcma_core_pci_{up,down}() functions as it tries to schedule
thus requiring to call them from non-atomic context. The function
bcma_core_pci_power_save() is now exported so the calling module
can explicitly use it in non-atomic context. This fixes the
'scheduling while atomic' issue reported by Tod Jackson and
Joe Perches.

[   13.210710] BUG: scheduling while atomic: dhcpcd/1800/0x00000202
[   13.210718] Modules linked in: brcmsmac nouveau coretemp kvm_intel kvm cordic brcmutil bcma dell_wmi atl1c ttm mxm_wmi wmi
[   13.210756] CPU: 2 PID: 1800 Comm: dhcpcd Not tainted 3.11.0-wl #1
[   13.210762] Hardware name: Alienware M11x R2/M11x R2, BIOS A04 11/23/2010
[   13.210767]  ffff880177c92c40 ffff880170fd1948 ffffffff8169af5b 0000000000000007
[   13.210777]  ffff880170fd1ab0 ffff880170fd1958 ffffffff81697ee2 ffff880170fd19d8
[   13.210785]  ffffffff816a19f5 00000000000f4240 000000000000d080 ffff880170fd1fd8
[   13.210794] Call Trace:
[   13.210813]  [<ffffffff8169af5b>] dump_stack+0x4f/0x84
[   13.210826]  [<ffffffff81697ee2>] __schedule_bug+0x43/0x51
[   13.210837]  [<ffffffff816a19f5>] __schedule+0x6e5/0x810
[   13.210845]  [<ffffffff816a1c34>] schedule+0x24/0x70
[   13.210855]  [<ffffffff816a04fc>] schedule_hrtimeout_range_clock+0x10c/0x150
[   13.210867]  [<ffffffff810684e0>] ? update_rmtp+0x60/0x60
[   13.210877]  [<ffffffff8106915f>] ? hrtimer_start_range_ns+0xf/0x20
[   13.210887]  [<ffffffff816a054e>] schedule_hrtimeout_range+0xe/0x10
[   13.210897]  [<ffffffff8104f6fb>] usleep_range+0x3b/0x40
[   13.210910]  [<ffffffffa00371af>] bcma_pcie_mdio_set_phy.isra.3+0x4f/0x80 [bcma]
[   13.210921]  [<ffffffffa003729f>] bcma_pcie_mdio_write.isra.4+0xbf/0xd0 [bcma]
[   13.210932]  [<ffffffffa0037498>] bcma_pcie_mdio_writeread.isra.6.constprop.13+0x18/0x30 [bcma]
[   13.210942]  [<ffffffffa00374ee>] bcma_core_pci_power_save+0x3e/0x80 [bcma]
[   13.210953]  [<ffffffffa003765d>] bcma_core_pci_up+0x2d/0x60 [bcma]
[   13.210975]  [<ffffffffa03dc17c>] brcms_c_up+0xfc/0x430 [brcmsmac]
[   13.210989]  [<ffffffffa03d1a7d>] brcms_up+0x1d/0x20 [brcmsmac]
[   13.211003]  [<ffffffffa03d2498>] brcms_ops_start+0x298/0x340 [brcmsmac]
[   13.211020]  [<ffffffff81600a12>] ? cfg80211_netdev_notifier_call+0xd2/0x5f0
[   13.211030]  [<ffffffff815fa53d>] ? packet_notifier+0xad/0x1d0
[   13.211064]  [<ffffffff81656e75>] ieee80211_do_open+0x325/0xf80
[   13.211076]  [<ffffffff8106ac09>] ? __raw_notifier_call_chain+0x9/0x10
[   13.211086]  [<ffffffff81657b41>] ieee80211_open+0x71/0x80
[   13.211101]  [<ffffffff81526267>] __dev_open+0x87/0xe0
[   13.211109]  [<ffffffff8152650c>] __dev_change_flags+0x9c/0x180
[   13.211117]  [<ffffffff815266a3>] dev_change_flags+0x23/0x70
[   13.211127]  [<ffffffff8158cd68>] devinet_ioctl+0x5b8/0x6a0
[   13.211136]  [<ffffffff8158d5c5>] inet_ioctl+0x75/0x90
[   13.211147]  [<ffffffff8150b38b>] sock_do_ioctl+0x2b/0x70
[   13.211155]  [<ffffffff8150b681>] sock_ioctl+0x71/0x2a0
[   13.211169]  [<ffffffff8114ed47>] do_vfs_ioctl+0x87/0x520
[   13.211180]  [<ffffffff8113f159>] ? ____fput+0x9/0x10
[   13.211198]  [<ffffffff8106228c>] ? task_work_run+0x9c/0xd0
[   13.211202]  [<ffffffff8114f271>] SyS_ioctl+0x91/0xb0
[   13.211208]  [<ffffffff816aa252>] system_call_fastpath+0x16/0x1b
[   13.211217] NOHZ: local_softirq_pending 202

The issue was introduced in v3.11 kernel by following commit:

commit aa51e598d04c6acf5477934cd6383f5a17ce9029
Author: Hauke Mehrtens <hauke@hauke-m.de>
Date:   Sat Aug 24 00:32:31 2013 +0200

    brcmsmac: use bcma PCIe up and down functions

    replace the calls to bcma_core_pci_extend_L1timer() by calls to the
    newly introduced bcma_core_pci_ip() and bcma_core_pci_down()

    Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
    Cc: Arend van Spriel <arend@broadcom.com>
    Signed-off-by: John W. Linville <linville@tuxdriver.com>
This fix has been discussed with Hauke Mehrtens [1] selection
option 3) and is intended for v3.12.

Ref:
[1] http://mid.gmane.org/5239B12D.3040206@hauke-m.de

Cc: <stable@vger.kernel.org> # 3.11.x
Cc: Tod Jackson <tod.jackson@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: Rafal Milecki <zajec5@gmail.com>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>