Staging: gdm72xx: Add space around that "+", "&" and "/"

Add missing spaces around "+", "&" and "/" to follow kernel coding
style. Warning detected by checkpatch.

Signed-off-by: Shraddha Barke <shraddha.6596@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>