ARM: OMAP4+: PRM: Add AM437x specific data

The register offsets for some of the PRM Registers are different
hence populating the differing fields. This is needed to support
IO wake up feature for am437x family.

Signed-off-by: Keerthy <j-keerthy@ti.com>
Reviewed-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>