[ARM] S3C64XX: GPIO include cleanup

Cleanup arm/plat-s3c64xx/include/plat/gpio-bank-h.h include file.
Using shift-left operation with value >32 is a bad habit.

Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>