GLSurfaceView: add property to default to RGB565

Some legacy devices (like the Xoom) are not capable of handling
RGB888 surfaces, which is now the default. This results in some
OpenGL apps crashing with "No config chosen" errors.

Set ro.opengles.surface.rgb565=true to go back to the old default
of RGB565 surfaces.

Credit to dreamcwli for the original patch.

Change-Id: I5ad9aa8e98eb6fd554b01022439141fe4a55bd70