This patch merges omap2 PM code from N800 tree.

Patch adds support for sleep while idle for omap2
and handy serial console debbugging code. It also
moves code from pm-domain.c to pm.c.

This code can be used as a base for developing
power management for all omap24xx boards.
Signed-off-by: Kai Svahn <kai.svahn@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>