Don't force GPU composite for older devices

Older devices (8960) don't take this very well in programs like
Netflix. Modeled on 94b8632b85e2b6588a1b3260d1f4e48462501d4b

Change-Id: Ie716bbfb6f6560d8f9f52b7b72ca0b04d1bad6b8
hwc: Blank and unblank primary on first boot

Change-Id: I246858f216d58e2e96a1faf1afac60372f3ddcab