media: staging: atomisp: Fix compat IOCTL handling

Atomisp compat IOCTL handling suffers from the same security issue than
the V4L2 did. Fix this for atomisp.

See more information in patch a1dfb4c4 ("media: v4l2-compat-ioctl32.c:
refactor compat ioctl32 logic").

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>