dt-bindings: pinctrl: mediatek,mt7622-pinctrl: Add missing base reg

dt-bindings: pinctrl: mediatek,mt7622-pinctrl: Add missing base reg

The pin controller for both MT7622 and MT7629 need both a "base"
and an "eint" MMIO like the ones found on other MediaTek SoCs:
while devicetrees have always been correct, the binding is not,
as it only allows an "eint" reg.

Add "base" to reg-names and increment maxItems for reg to two.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>