staging: cxd2099: Add spaces around arithmetical operators

Added spaces around multiple arithmetical operators
to fix the checkpatch.pl issue: CHECK: spaces preferred around that 'operator'.

Signed-off-by: Tamara Diaconita <diaconita.tamara@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>