ARM: S3C64XX: Support GPIO LEDs on Cragganmore

Cragganmore has a bank of 8 LEDs connected to the memory mapped GPIO
bank, mostly intended for low level diagnostics. Register these with
the LED subsystem for runtime use.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>