wl12xx: fix race between suspend/resume and recovery

The iteration on the wlvif list in wl1271_op_resume/suspend was
perfomed before locking wl->mutex which would lead to a kernel
panic in case a recovery was queued at the same time
and would delete the wlvifs from the list.

Signed-off-by: Eyal Shapira <eyal@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>