android: add support for r600g

Tested with a Radeon HD 6250.  SurfaceFlinger (the display server and
compositor) works.  2D apps with RGB or RGBA visuals work.  As for 3D
apps, some work but some don't (with serious rendering defects).

Reviewed-by: Marek Olšák <maraeo@gmail.com>

Android.mk

@@ -24,7 +24,7 @@
 # BOARD_GPU_DRIVERS should be defined.  The valid values are
 #
 #   classic drivers:
-#   gallium drivers: swrast
+#   gallium drivers: swrast r600g
 #
 # The main target is libGLES_mesa.  There is no classic drivers yet.
 
@@ -36,7 +36,7 @@ DRM_TOP := external/drm
 DRM_GRALLOC_TOP := hardware/drm_gralloc
 
 classic_drivers :=
-gallium_drivers := swrast
+gallium_drivers := swrast r600g
 
 MESA_GPU_DRIVERS := $(BOARD_GPU_DRIVERS)
 
@@ -110,6 +110,12 @@ gallium_DRIVERS :=
 # swrast
 gallium_DRIVERS += libmesa_pipe_softpipe libmesa_winsys_sw_android
 
+# r600g
+ifneq ($(filter r600g, $(MESA_GPU_DRIVERS)),)
+gallium_DRIVERS += libmesa_winsys_radeon
+gallium_DRIVERS += libmesa_pipe_r600 libmesa_winsys_r600
+endif
+
 #
 # Notes about the order here:
 #