MAINTAINERS: Update with Amlogic DRM bindings converted as YAML

The amlogic,meson-dw-hdmi.txt and amlogic,meson-vpu.txt has been
converted to YAML schemas, update MAINTAINERS to match them again.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Maxime Jourdan <mjourdan@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190808085522.21950-4-narmstrong@baylibre.com

MAINTAINERS

@@ -5336,8 +5336,8 @@ L:	linux-amlogic@lists.infradead.org
 W:	http://linux-meson.com/
 S:	Supported
 F:	drivers/gpu/drm/meson/
-F:	Documentation/devicetree/bindings/display/amlogic,meson-vpu.txt
-F:	Documentation/devicetree/bindings/display/amlogic,meson-dw-hdmi.txt
+F:	Documentation/devicetree/bindings/display/amlogic,meson-vpu.yaml
+F:	Documentation/devicetree/bindings/display/amlogic,meson-dw-hdmi.yaml
 F:	Documentation/gpu/meson.rst
 T:	git git://anongit.freedesktop.org/drm/drm-misc