mwifiex: add firmware dump feature for PCIe

mwifiex: add firmware dump feature for PCIe

Firmware dump feature is added for PCIe based chipsets which can
be used with the help of ethtool commands.

1) Trigger firmware dump operation:
ethtool --set-dump mlan0 0xff

When the operation is completed, udev event will be sent to
trigger external application.

2) Following udev rule can be used to get the data from ethtool:
DRIVER=="mwifiex_pcie", ACTION=="change", RUN+="/sbin/mwifiex_pcie_fw_dump.sh"

mwifiex_pcie_fw_dump.sh: #!/bin/bash
ethtool --set-dump mlan0 0
ethtool --get-dump mlan0
ethtool --get-dump mlan0 data /tmp/ITCM.log

ethtool --set-dump mlan0 1
ethtool --get-dump mlan0
ethtool --get-dump mlan0 data /tmp/DTCM.log

ethtool --set-dump mlan0 2
ethtool --get-dump mlan0
ethtool --get-dump mlan0 data /tmp/SQRAM.log

ethtool --set-dump mlan0 3
ethtool --get-dump mlan0
ethtool --get-dump mlan0 data /tmp/IRAM.log

Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>