OMAP4: PRCM: Add offset defines for all CM registers

The cm44xx.h files only had absolute register address
defines for all CM registers.
This patch adds additional register offset defines for all the
registers, so they can be used with apis like cm_read_mod_*

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