ARM: S5P: Move the SROM register definitions to plat-s5p

The SROM register difinitions of S5PV310/S5PC210 (mach/regs-srom.h)
can be used to other S5P SoCs such as S5PV210/S5PC110. So moved into
plat/regs-srom.h of plat-s5p directory.

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