mwifiex: save driver information to file when firmware dump

This patch adds support to dump driver information to a file
when firmware dump happens. This information can be used to
root casue FW crash.

Signed-off-by: Xinming Hu <huxm@marvell.com>
Signed-off-by: Cathy Luo <cluo@marvell.com>
Signed-off-by: Avinash Patil <patila@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>