wl12xx: Avoid recovery while one is already in progress

During recovery work commands sent to the FW could fail and schedule
additional recovery work. Since the chip is going to be powered off,
avoid recursive recoveries.

Signed-off-by: Ido Yariv <ido@wizery.com>
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>