mt76: mt7921: fix invalid register access in wake_work

mt76: mt7921: fix invalid register access in wake_work

Make sure mt7921_pm_wake_work wouldn't be scheduled after the driver is
in suspend mode to fix the following the kernel crash.

[ 3515.390012] mt7921e 0000:01:00.0: calling pci_pm_suspend+0x0/0x22c @ 2869, parent: 0000:00:00.0
[ 3515.390015] mt7921e 0000:01:00.0: mt7921_pci_suspend +
[ 3515.396395] anx7625 3-0058: anx7625_suspend+0x0/0x6c returned 0 after 0 usecs
[ 3515.405965] mt7921e 0000:01:00.0: mt7921_pci_suspend -
[ 3515.411336] usb 1-1.4: usb_dev_suspend+0x0/0x2c returned 0 after 1 usecs
[ 3515.411513] SError Interrupt on CPU7, code 0xbe000011 -- SError
[ 3515.411515] CPU: 7 PID: 2849 Comm: kworker/u16:27 Not tainted 5.4.114 #44
[ 3515.411516] Hardware name: MediaTek Asurada rev1 board (DT)
[ 3515.411517] Workqueue: mt76 mt7921_pm_wake_work [mt7921e]
[ 3515.411518] pstate: 80c00009 (Nzcv daif +PAN +UAO)
[ 3515.411519] pc : mt76_mmio_rr+0x30/0xf0 [mt76]
[ 3515.411520] lr : mt7921_rr+0x38/0x44 [mt7921e]
[ 3515.411520] sp : ffffffc015813c50
[ 3515.411521] x29: ffffffc015813c50 x28: 0000000000000402
[ 3515.411522] x27: ffffffe5a2012138 x26: ffffffe5a1eea018
[ 3515.411524] x25: 00000000328be505 x24: 00000000000a0002
[ 3515.411525] x23: 0000000000000006 x22: ffffffbd29b7a300
[ 3515.411527] x21: ffffffbd29b7a300 x20: 00000000000e0010
[ 3515.411528] x19: 00000000eac08f43 x18: 0000000000000000
[ 3515.411529] x17: 0000000000000000 x16: ffffffe5a16b2914
[ 3515.411531] x15: 0000000000000010 x14: 0000000000000010
[ 3515.411532] x13: 00000000003dd3a2 x12: 0000000000010000
[ 3515.411533] x11: ffffffe597abec14 x10: 0000000000000010
[ 3515.411535] x9 : ffffffe597abeba8 x8 : ffffffc013ce0010
[ 3515.411536] x7 : 000000b2b5593519 x6 : 0000000000300000
[ 3515.411537] x5 : 0000000000000000 x4 : 0000000000000032
[ 3515.411539] x3 : 0000000000000000 x2 : 0000000000000004
[ 3515.411540] x1 : 00000000000e0010 x0 : ffffffbd29b7a300
[ 3515.411542] Kernel panic - not syncing: Asynchronous SError Interrupt
[ 3515.411543] CPU: 7 PID: 2849 Comm: kworker/u16:27 Not tainted 5.4.114 #44
[ 3515.411544] Hardware name: MediaTek Asurada rev1 board (DT)
[ 3515.411544] Workqueue: mt76 mt7921_pm_wake_work [mt7921e]
[ 3515.411545] Call trace:
[ 3515.411546]  dump_backtrace+0x0/0x14c
[ 3515.411546]  show_stack+0x20/0x2c
[ 3515.411547]  dump_stack+0xa0/0xfc
[ 3515.411548]  panic+0x154/0x350
[ 3515.411548]  panic+0x0/0x350
[ 3515.411549]  arm64_serror_panic+0x78/0x84
[ 3515.411550]  do_serror+0x0/0x118
[ 3515.411550]  do_serror+0xa4/0x118
[ 3515.411551]  el1_error+0x84/0xf8
[ 3515.411552]  mt76_mmio_rr+0x30/0xf0 [mt76]
[ 3515.411552]  mt7921_rr+0x38/0x44 [mt7921e]
[ 3515.411553]  __mt76_poll_msec+0x5c/0x9c [mt76]
[ 3515.411554]  __mt7921_mcu_drv_pmctrl+0x50/0x94 [mt7921e]
[ 3515.411555]  mt7921_mcu_drv_pmctrl+0x38/0xb0 [mt7921e]
[ 3515.411555]  mt7921_pm_wake_work+0x34/0xd4 [mt7921e]
[ 3515.411556]  process_one_work+0x208/0x3c8
[ 3515.411557]  worker_thread+0x23c/0x3e8
[ 3515.411557]  kthread+0x144/0x178
[ 3515.411558]  ret_from_fork+0x10/0x18
[ 3515.418831] SMP: stopping secondary CPUs
[ 3515.418832] Kernel Offset: 0x2590c00000 from 0xffffffc010000000
[ 3515.418832] PHYS_OFFSET: 0xffffffc400000000
[ 3515.418833] CPU features: 0x080026,2a80aa18
[ 3515.418834] Memory Limit: none
[DL] 00000000 00000000 010701

Fixes: 1d8efc741df80 ("mt76: mt7921: introduce Runtime PM support")
Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>