MAINTAINERS: Update drm/rcar-du maintainers

Update drm/rcar-du maintainer entries:

* Add myself as drm/rcar-du maintainer.
* Update Laurent's email to include +renesas.
* Switch Kieran from a maintainer to reviewer.
* Change rcar-du to be under drm-misc umbrella.

Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250128-rcar-du-maintainers-v2-1-4a3860a3e1ef@ideasonboard.com

MAINTAINERS

@@ -7604,7 +7604,6 @@ X:	drivers/gpu/drm/mediatek/
 X:	drivers/gpu/drm/msm/
 X:	drivers/gpu/drm/nouveau/
 X:	drivers/gpu/drm/radeon/
-X:	drivers/gpu/drm/renesas/rcar-du/
 X:	drivers/gpu/drm/tegra/
 
 DRM DRIVERS FOR ALLWINNER A10
@@ -7759,12 +7758,13 @@ F:	include/linux/host1x.h
 F:	include/uapi/drm/tegra_drm.h
 
 DRM DRIVERS FOR RENESAS R-CAR
-M:	Laurent Pinchart <laurent.pinchart@ideasonboard.com>
-M:	Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
+M:	Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
+M:	Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
+R:	Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
 L:	dri-devel@lists.freedesktop.org
 L:	linux-renesas-soc@vger.kernel.org
 S:	Supported
-T:	git git://linuxtv.org/pinchartl/media drm/du/next
+T:	git https://gitlab.freedesktop.org/drm/misc/kernel.git
 F:	Documentation/devicetree/bindings/display/bridge/renesas,dsi-csi2-tx.yaml
 F:	Documentation/devicetree/bindings/display/bridge/renesas,dw-hdmi.yaml
 F:	Documentation/devicetree/bindings/display/bridge/renesas,lvds.yaml