dt-bindings: pinctrl: Document optional BCM7211 wake-up interrupts

BCM7211 supports wake-up interrupts in the form of optional interrupt
lines, one per bank, plus the "all banks" interrupt line.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200531001101.24945-3-f.fainelli@gmail.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/brcm,bcm2835-gpio.txt

@@ -16,7 +16,9 @@ Required properties:
   second cell is used to specify optional parameters:
   - bit 0 specifies polarity (0 for normal, 1 for inverted)
 - interrupts : The interrupt outputs from the controller. One interrupt per
-  individual bank followed by the "all banks" interrupt.
+  individual bank followed by the "all banks" interrupt. For BCM7211, an
+  additional set of per-bank interrupt line and an "all banks" wake-up
+  interrupt may be specified.
 - interrupt-controller: Marks the device node as an interrupt controller.
 - #interrupt-cells : Should be 2.
   The first cell is the GPIO number.