drm/radeon: Deprecate UMS support v2

KMS support is out and stable for a couple of years now and
the userspace code has deprecated or abandoned the old UMS interface.

So make the KMS interface the default and deprecate the UMS interface
in the kernel as well.

v2: rebased on alex/drm-next-3.9-wip

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 983201b..3399b20 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -96,6 +96,7 @@
         select DRM_TTM
 	select POWER_SUPPLY
 	select HWMON
+	select BACKLIGHT_CLASS_DEVICE
 	help
 	  Choose this option if you have an ATI Radeon graphics card.  There
 	  are both PCI and AGP versions.  You don't need to choose this to