ARM: S5P: Add SROM control register shift macros for other banks.

This patch adds shift macros for the SROM Bus width and control
register to represent the shift count for the 5th and 6th SROM
banks.  Some of the S5P SOCs have them.

Signed-off-by: Thomas Abraham <thomas.ab@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>