wlcore: Fix unbalanced interrupts enablement

The interrupt line is enabled by wl12xx_enable_interrupts and
wl18xx_enable_interrupts, but it will not be disabled in all failure
paths. Fix this.

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