OMAP2/3: PRM: add module hard reset support

This patch adds hard-reset support for processor modules (e.g., DSP, IVA)
on OMAP2/3 platforms.  It's based on the OMAP4 hard-reset support that Benoît
developed in the previous patch.

This patch is a collaboration between Benoît Cousson <b-cousson@ti.com>
and Paul Walmsley <paul@pwsan.com>.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Benoît Cousson <b-cousson@ti.com>