dt-bindings: pinctrl: Convert marvell,armada-3710-(sb|nb)-pinctrl to DT schema

dt-bindings: pinctrl: Convert marvell,armada-3710-(sb|nb)-pinctrl to DT schema

Convert the marvell,armada3710-(sb|nb)-pinctrl binding to DT schema
format. The binding includes the "marvell,armada-3700-xtal-clock"
subnode which is simple enough to include here.

Mark interrupt-controller/#interrupt-cells as required as the users have
them and the h/w is either capable of interrupts or not.

As this syscon has 2 register ranges, syscon-common.yaml needs to be
updated to drop the restriction of 1 register entry.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>