media: atomisp: remove dublicate code

Removed dublicate returns and breaks inside switch
statements and useless return after switch.

Link: https://lore.kernel.org/linux-media/3944cd10bb5a64157781b1e0ef044c62c05f07c7.1620479607.git.paskripkin@gmail.com


Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>