dt-bindings: tpm: Convert Google Cr50 bindings to DT schema

dt-bindings: tpm: Convert Google Cr50 bindings to DT schema

Convert the devicetree bindings for the Google Security Chip H1 running
Cr50 firmware to DT schema.

The chip can be attached to SPI or I²C.  Existing devicetrees use the
same "google,cr50" compatible string for both cases without additionally
specifying a generic "tcg,tpm_tis-spi" or "tcg,tpm-tis-i2c" compatible.

The chip therefore cannot be documented in the tcg,tpm_tis-spi.yaml and
tcg,tpm-tis-i2c.yaml schemas:  The validator would select both of them
and complain about SPI properties when the chip is an I²C peripheral.

So document the chip in a schema of its own which includes both, SPI and
I²C properties by reference.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/52635205818ab201cacb0c0f37c7fa48149c7f8e.1702806810.git.lukas@wunner.de
Signed-off-by: Rob Herring <robh@kernel.org>