media: staging: rkisp1: unify (un)register functions to have the same parameters

The different register/unregister functions receive
different parameters. This patch unify them so they all receive just
'struct *rkisp1_device' as parameter.

Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Acked-by: Helen Koike <helen.koike@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>