staging: media: atomisp: Compress return logic into one line.

Simplify function return by merging assignment and return into a single
line. The following coccinelle script is used to fix this issue.

@@
expression e;
local idexpression ret;
@@

-ret = e;
-return ret;
+return e;

This patch also removes unnecessary declarations.

Signed-off-by: Varsha Rao <rvarsha016@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>