MAINTAINERS: exynos: Add EXYNOS DRM maintainer entry

As Exynos DRM is merged at mainline. Also update the maintainer entry.
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

MAINTAINERS

@@ -2342,6 +2342,13 @@ S:	Supported
 F:	drivers/gpu/drm/i915
 F:	include/drm/i915*
 
+DRM DRIVERS FOR EXYNOS
+M:	Inki Dae <inki.dae@samsung.com>
+L:	dri-devel@lists.freedesktop.org
+S:	Supported
+F:	drivers/gpu/drm/exynos
+F:	include/drm/exynos*
+
 DSCC4 DRIVER
 M:	Francois Romieu <romieu@fr.zoreil.com>
 L:	netdev@vger.kernel.org