linux-wandboard

arm/imx/gpio: remove a BUG_ON in hot path

Now if the problem occurs that triggered the BUG_ON before, the machine
runs in a NULL pointer dereference.  So it wouldn't be much harder now
to debug the situation if it occured.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>