media: amphion: fix some issues to improve robust

fix some issues reported by Dan,
1. fix some signedness bug
2. don't use u32 as function return value
3. prevent a divide by zero bug
4. Just return zero on success, don't return a known parameter
5. check the validity of some variables
6. reset buffer state when return buffers
7. make sure the ALIGN won't wrap to zero

Signed-off-by: Ming Qian <ming.qian@nxp.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>