Keyboard light: Fix the physical keyboard not light when it's visiable.

Change-Id: I595afd3cb6b422a17ae0f6ec20aa51979db13810
policy: always use hardware acceleration for keyguard

Without hardware acceleration, keyguard widget will appear aliased
and choppy (especially at the end of the scroll).

Change-Id: I1bfb6fbcba6306edf366e8ea752d6919936c3ab6

Conflicts:
	policy/src/com/android/internal/policy/impl/keyguard/KeyguardViewManager.java