MAINTAINERS: update entry for drm/msm

We've moved the tree to a shared gitlab tree, so that Sean can help out
with maintainer duties.

Cc: Sean Paul <seanpaul@chromium.org>
Acked-by: Sean Paul <sean@poorly.run>
Signed-off-by: Rob Clark <robdclark@gmail.com>

MAINTAINERS

@@ -4830,10 +4830,11 @@ F:	Documentation/devicetree/bindings/display/multi-inno,mi0283qt.txt
 
 DRM DRIVER FOR MSM ADRENO GPU
 M:	Rob Clark <robdclark@gmail.com>
+M:	Sean Paul <sean@poorly.run>
 L:	linux-arm-msm@vger.kernel.org
 L:	dri-devel@lists.freedesktop.org
 L:	freedreno@lists.freedesktop.org
-T:	git git://people.freedesktop.org/~robclark/linux
+T:	git https://gitlab.freedesktop.org/drm/msm.git
 S:	Maintained
 F:	drivers/gpu/drm/msm/
 F:	include/uapi/drm/msm_drm.h