MAINTAINERS: dri-devel is for all of drivers/gpu

Somehow we only have a list of subdirectories, which apparently made
it harder for folks to find the gpu maintainers. Fix that.

References: https://lore.kernel.org/dri-devel/YXrAAZlxxStNFG%[email protected]/
Signed-off-by: Daniel Vetter <[email protected]>
Reviewed-by: Alex Deucher <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: Steven Rostedt <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: danvet

MAINTAINERS

@@ -6147,8 +6147,7 @@ T:	git git://anongit.freedesktop.org/drm/drm
 F:	Documentation/devicetree/bindings/display/
 F:	Documentation/devicetree/bindings/gpu/
 F:	Documentation/gpu/
-F:	drivers/gpu/drm/
-F:	drivers/gpu/vga/
+F:	drivers/gpu/
 F:	include/drm/
 F:	include/linux/vga*
 F:	include/uapi/drm/