Fix gpio-config off-by-one bug. Without this patch, touching GPA0 pin on
S3C64XX platform causes kernel oops.
Reviewed-by: NKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NBen Dooks <ben-linux@fluff.org>