wlcore: Disable interrupts while recovering

In case a recovery is initiated, the FW can no longer be trusted, and
the driver should not handle any new FW events.

Disable the interrupt handler when a recovery is scheduled and balance
it back in the op_stop callback.

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