media: atomisp: add a default case at __get_frame_info()

The switch() logic there misses a break and a default case.
That makes it more prone to problems as the code change.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>