USB: gadget: s3c-hsotg: missing parentheses

Add missing parentheses

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
CC: Ben Dooks <ben@simtec.co.uk>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>