dt-bindings: mmc: mmc-pwreq-simple: Accept more than one reset GPIO

There might be multiple reset GPIOs but dtschema has trouble parsing it
if there are no maxItems:

  arch/arm/boot/dts/exynos5250-snow.dt.yaml: mmc3_pwrseq: reset-gpios: [[20, 2, 1], [20, 1, 1]] is too long
    From schema: Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.yaml
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200831161147.13515-2-krzk@kernel.orgSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.yaml

@@ -20,6 +20,8 @@ properties:
 
   reset-gpios:
     minItems: 1
+    # Put some limit to avoid false warnings
+    maxItems: 32
     description:
       contains a list of GPIO specifiers. The reset GPIOs are asserted
       at initialization and prior we start the power up procedure of the card.