Power HAL: disable KSM scanning when screen is off

KSM scanning can keep the CPU busy during otherwise idle periods, which
hurts battery life.  Therefore, when KSM is in use, disable KSM scanning
before the screen turns off and reenable it when the screen turns back
on.

Change-Id: Id577977d0b6bc7c2456334726552a6723c83593f
Disable use of YUV overlay hardware in the OMAP3 HWC

Using YUV overlays causes rendering glitches and display sync loss
when playing back certain videos, so disable their use.  (It's unclear
at this point whether this is a limitation of the hardware or a driver
bug.)

Change-Id: Ia3d8fb7aadf04feaa01cbea29962e76e224052cd
Rename custom recovery keymapping file to match original source

The corresponding keymapping file in the recovery source is now
default_recovery_keys.c, and recovery_ui now typically refers to a
separate device-overridable file (which we want to override in the
future).

Change-Id: I0bde1213fcae08a61915b98da726972122dd65d2
recovery_ui: update for CWM API changes

CWM's eliminating device_toggle_display() and
ui_get_showing_back_button() (see http://review.cyanogenmod.org/62724).
Remove these in our recovery_ui.c.

Change-Id: Ib26ffdf04194dc0f916934bf1bc1b92b47938ee2