s3c: DeviceTree bits for s3c24xx GPIO

Hi,

here are the first bits to add DT to the GPIO controller of s3c24xx.

cheers,
Domenico

-----[ Domenico Andreoli, aka cavok
--[ http://www.dandreoli.com/gpgkey.asc
---[ 3A0F 2F80 F79C 678A 8936 4FEE 0677 9033 A20E BC50