ARM: S5PC100: Use generic S5P GPIO Interrupt interface

S5PC100 SoC can use common S5P GPIO interrupt code. This patch
removes specific S5PC100 gpio interrupts code and adds required
defines and code to make use of common S5P code.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>