OMAP4: cm: Remove RESTORE macros to avoid access from SW

The restore part of the CM is an alias of some regular registers
used only during the SAR restore to facilate the dma to write
a contiguous set of registers.
The registers should never be used by the SW, only the original
register have to be used.

Remove them from cmX_44xx.h files to avoid anybody to use them by
mistake.

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