staging: sm750fb: add spaces around operators

Fixes checkpath.pl error:
ERROR: spaces required around that operator

Note running checkpatch.pl with '--strict' catches more
of these errors along with cases where spacing is optional
but preferred. Take care of these in a future patch.

Signed-off-by: Juston Li <juston.h.li@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>