surfacetexture: Select texture target based on pixel format

Adreno is not optimized for GL_TEXTURE_EXTERNAL_OES, making GPU
utilization (and power), high with GL_TEXTURE_EXTERNAL_OES for
RGB formats.

Change texture target from GL_EXTERNAL_TEXTURE_OES to dynamically
select between GL_EXTERNAL_TEXTURE_OES, and GL_TEXTURE_2D based
on the pixel format.

This change is done to reduce the composition time for 8x55

*Ported from ics
*ifdef for BOARD_ADRENO_DECIDE_TEXTURE_TARGET

Change-Id: I33c96bf09fbad0f3fe4ca84c796fca78db51704f

Conflicts:
	services/surfaceflinger/Android.mk