egl: Reintroduce eglGetRenderBufferANDROID

eglGetRenderBufferANDROID was removed as it had no users. This commit
reintroduces this extensions as it's used by Qualcomm graphics HAL.

Change-Id: I493306830a0d4f8722a42bcc84fb49236afdabeb

Conflicts:
	opengl/libs/EGL/eglApi.cpp