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

Another issue found by KASAN. The bit finding is buried inside the
dp_for_each_set_bit() macro (that passes on to for_each_set_bit() that
calls the bit stuff. These bit functions want an unsigned long pointer
as input and just dumbly casting leads to out-of-bounds accesses.
This fixes that.

Signed-off-by: Carsten Haitzler <carsten.haitzler@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: James Qian Wang <james.qian.wang@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210204131102.68658-1-carsten.haitzler@foss.arm.com