dt-bindings: pinctrl: qcom: Add SDX65 pinctrl bindings

Add device tree binding Documentation details for Qualcomm SDX65
pinctrl driver.

Signed-off-by: Vamsi Krishna Lanka <quic_vamslank@quicinc.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/06234768890dc7572226f23d432e5a69a4d5b305.1637048107.git.quic_vamslank@quicinc.com


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