dt-bindings: pinctrl: qcom: add sdm670 pinctrl

There is a new driver for the Snapdragon 670 TLMM (Top-Level Mode
Multiplexer). Document it.

Adapted from qcom,sm6350-pinctrl.yaml.

Signed-off-by: Richard Acayan <mailingradian@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221014001934.4995-2-mailingradian@gmail.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>