dt-bindings: tpm: Add st,st33ktpm2xi2c

Add the ST chip st33ktpm2xi2c to the supported compatible strings of the
TPM TIS I2C schema. The Chip is compliant with the TCG PC Client TPM
Profile specification.

For reference, a datasheet is available at:
https://www.st.com/resource/en/data_brief/st33ktpm2xi2c.pdf

Reviewed-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Signed-off-by: Michael Haener <michael.haener@siemens.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>