drm/komeda: Fix bit check to import to value of proper type

KASAN found this problem. find_first_bit() expects to look at a
pointer pointing to a long, but we look at a u32 - this is going to be
an issue with endianess but, KSAN already flags this as out-of-bounds
stack reads. This fixes it by just importing inot a local long.

Signed-off-by: Carsten Haitzler <carsten.haitzler@arm.com>