ARM: DRA7: Reuse all of PRCM and MPUSS SMP infra

The PRCM and MPUSS parts of DRA7 devices are quite identical
to OMAP5 so as to reuse all the existing infrastructure around it.
Makefile updates to do just that.

Signed-off-by: R Sricharan <r.sricharan@ti.com>
Signed-off-by: Rajendra Nayak <rnayak@ti.com>