dt-bindings: pinctrl: qcom-pmic-gpio: Add support for PM/PMI8950

Document the bindings for PM8950 and PMI8950 PMIC GPIOs.

Signed-off-by: AngeloGioacchino Del Regno <kholk11@gmail.com>
Link: https://lore.kernel.org/r/20191031103507.30678-3-kholk11@gmail.com


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