tty: ipwireless: Fix probable mask then right shift defects

Precedence of & and >> is not the same and is not left to right.
shift has higher precedence and should be done after the mask.

Add parentheses around the masks.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: David Sterba <dsterba@suse.cz>
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>