allow paletted RGB images in recovery
allow paletted RGB images in recovery

Recovery assumes any paletted images are in RGBA format.  Make it
handle both RGB and RGBA paletted images.

Bug: 3514884
Change-Id: I517cd571aa3f434dacacc33a774236260aec20ef

DerTeufel/dualboot_recovery,InsomniaAOSP/platform_bootable_recovery,Plain-Andy/android_platform_bootable_recovery,InsomniaAOSP/platform_bootable_recovery,Plain-Andy/android_platform_bootable_recovery,76Demented/bootable_recovery-,kylinmoddev/android_bootable_recovery,randomblame/bootable_recovery,76Demented/bootable_recovery-,randomblame/bootable_recovery,InsomniaAOSP/platform_bootable_recovery,DerTeufel/dualboot_recovery,Plain-Andy/android_platform_bootable_recovery,DerTeufel/dualboot_recovery,DerTeufel/dualboot_recovery,76Demented/bootable_recovery-,randomblame/bootable_recovery,kylinmoddev/android_bootable_recovery,kylinmoddev/android_bootable_recovery,randomblame/bootable_recovery,kylinmoddev/android_bootable_recovery,76Demented/bootable_recovery-,InsomniaAOSP/platform_bootable_recovery,Plain-Andy/android_platform_bootable_recovery,randomblame/bootable_recovery,76Demented/bootable_recovery-,DerTeufel/dualboot_recovery,InsomniaAOSP/platform_bootable_recovery