gma500: mark staging broken

It now clashes with upstream DRM which we don't want to block.

We don't want to delete this code just yet as we want to keep it for
comparison and reference when debugging, but soon it will be a removal
candidate as well
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Cc: linux-next@vger.kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/gma500/Kconfig

 config DRM_PSB
 	tristate "Intel GMA5/600 KMS Framebuffer"
-	depends on DRM && PCI && X86
+	depends on DRM && PCI && X86 && BROKEN
 	select FB_CFB_COPYAREA
         select FB_CFB_FILLRECT
         select FB_CFB_IMAGEBLIT