Cortex-A8: hook up DPM

Cortex-A8: hook up DPM

This replaces two versions of register access functions.  One
was commented out, and seemed to have uncertain intent.  The
other was fairly new, and helped motivate the DPM framework
once I observed that the ARM11 was doing the very same ops.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>