MAINTAINERS: Rectify entry for NVIDIA TEGRA DRM and VIDEO DRIVER

Commit fd27de58b0ad ("dt-bindings: display: tegra: Convert to json-schema")
converts nvidia,tegra20-host1x.txt to yaml, but missed to adjust its
references in MAINTAINERS.

Hence, ./scripts/get_maintainer.pl --self-test=patterns complains about a
broken reference.

Repair these file references in NVIDIA TEGRA DRM and VIDEO DRIVER.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

MAINTAINERS

@@ -6707,7 +6707,7 @@ L:	dri-devel@lists.freedesktop.org
 L:	linux-tegra@vger.kernel.org
 S:	Supported
 T:	git git://anongit.freedesktop.org/tegra/linux.git
-F:	Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.txt
+F:	Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.yaml
 F:	Documentation/devicetree/bindings/gpu/host1x/
 F:	drivers/gpu/drm/tegra/
 F:	drivers/gpu/host1x/
@@ -19630,7 +19630,7 @@ M:	Sowjanya Komatineni <skomatineni@nvidia.com>
 L:	linux-media@vger.kernel.org
 L:	linux-tegra@vger.kernel.org
 S:	Maintained
-F:	Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.txt
+F:	Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.yaml
 F:	drivers/staging/media/tegra-video/
 
 TEGRA XUSB PADCTL DRIVER