media: staging: media: atomisp: Remove all redundant assertions in sh_css.c

Remove the remainder of assert() in places where the condition is
already handled.

Signed-off-by: Martiros Shakhzadyan <vrzh@vrzh.net>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>