dt-bindings: pinctrl: qcom: Document missing gpio nodes

The bindings for msm8998-pinctrl was missing gpio-ranges and
gpio-reserved-ranges, so document them as well

Signed-off-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20190702105045.27646-2-vkoul@kernel.org


Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>