dt-bindings: soc: ti: update sci-pm-domain.yaml references

Changeset fda55c72 ("dt-bindings: soc: ti: Convert ti,sci-pm-domain to json schema")
renamed: Documentation/devicetree/bindings/soc/ti/sci-pm-domain.txt
to: Documentation/devicetree/bindings/soc/ti/sci-pm-domain.yaml.

Update the cross-references accordingly.

Fixes: fda55c72 ("dt-bindings: soc: ti: Convert ti,sci-pm-domain to json schema")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/c03020ff281054c3bd2527c510659e05fec6f181.1622648507.git.mchehab+huawei@kernel.org


Signed-off-by: Rob Herring <robh@kernel.org>