ARM: S3C64XX: Use software initiated powerdown for Cragganmore

Since the two PMICs are independent we initiate a shutdown on each.

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