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>

Documentation/devicetree/bindings/pinctrl/qcom,msm8998-pinctrl.txt

@@ -40,6 +40,14 @@ MSM8998 platform.
 	Definition: must be 2. Specifying the pin number and flags, as defined
 		    in <dt-bindings/gpio/gpio.h>
 
+- gpio-ranges:
+	Usage: required
+	Definition:  see ../gpio/gpio.txt
+
+- gpio-reserved-ranges:
+	Usage: optional
+	Definition: see ../gpio/gpio.txt
+
 Please refer to ../gpio/gpio.txt and ../interrupt-controller/interrupts.txt for
 a general description of GPIO and interrupt bindings.
 
@@ -175,6 +183,8 @@ Example:
 		interrupts = <0 208 0>;
 		gpio-controller;
 		#gpio-cells = <2>;
+		gpio-ranges = <&tlmm 0 0 175>;
+		gpio-reserved-ranges = <0 4>, <81 4>;
 		interrupt-controller;
 		#interrupt-cells = <2>;