OMAP3: PM: Restore MMU table entry

During the MMU restoration on the restore path from MPU OFF, the page
table entry for the page consisting of the code being executed is
modified to make MMU return VA=PA.

The MMU is then enabled and the original entry is being stored in
scratchpad.  This patch reads the original values stored in
scratchpad, and restores them back.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>