ARM: OMAP4: PM: OMAP4 Power Domain Porting Related Clean-up.

Module offsets were same for OMAP2 and OMAP3 while they differ for OMAP4.
Hence we need different macros for identifying platform specific offsets.

Signed-off-by: Abhijit Pagare <abhijitpagare@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Rajendra Nayak <rnayak@ti.com>