Revert "wingray-common: disable scissor optimization"

This reverts commit ad686349698d757bc6a522a38e0e825edcf4d4d3.
wingray: use RGB565 surfaces

See http://review.cyanogenmod.org/#/c/29684/

Change-Id: I6d1dd9c7973d2cea8dc8ba2c05fb3118863cf802