gpio/samsung: fix broken configuration for EXYNOS4 GPIO banks

Commit 1b39d5f2 introduced new common gpio driver for all Samsung GPIO
SoCs. The new driver doesn't work correctly on Samsung Exynos4 SoC. It
fails to set configuration for all but external interrupt pins. This
patch fixes this issue.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>