staging: i4l: remove parens around return statement

Remove parentheses surrounding return statements. Error found by
checkpatch.

changes made using coccinelle script:

@@
expression e,e1;
@@
(
return (e / e1);
|
return
-(
e
-)
;
)

Signed-off-by: Elizabeth Ferdman <gnudevliz@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>