dt-bindings: pinctrl: Add DT schema for SM6375 TLMM

Document the TLMM driver for SM6375.

Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220716192900.454653-1-konrad.dybcio@somainline.org


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