mwifiex: wakeup pending wait queues

Wakeup pending wait queues in unload path. This will help to avoid
soft lockup issues in corner cases.

Signed-off-by: Cathy Luo <cluo@marvell.com>
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>