ARM: EXYNOS: support EINT for EXYNOS4 and EXYNOS5

The GPIOs of EXYNOS4 and EXYNOS5 are changed to use
ioremap instead of static mapping. It alse causes the
change of external interrupt IO mapping. This patch
changes EXYNOS4 to EXYNOS for common use and changes
EINT_x macros for supporting dynamic IO mapping.

Signed-off-by: Eunki Kim <eunki_kim@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>