MAINTAINERS: update nvidia,tegra20-host1x.yaml reference

Changeset fd27de58b0ad ("dt-bindings: display: tegra: Convert to json-schema")
renamed: Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.txt
to: Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.yaml.

Update its cross-reference accordingly.

Fixes: fd27de58b0ad ("dt-bindings: display: tegra: Convert to json-schema")
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Link: https://lore.kernel.org/r/e0adee01fe8064f981eb854e04fb64c4a0408b66.1656234456.git.mchehab@kernel.org


Signed-off-by: Jonathan Corbet <corbet@lwn.net>