dt-bindings: leds: lp55xx: switch to preferred 'gpios' suffix

dt-bindings: leds: lp55xx: switch to preferred 'gpios' suffix

The preferred name suffix for properties with single and multiple GPIOs
is "gpios".  Linux GPIO core code supports both.  The DTS has mixed
usage, so switch to preferred naming:

  omap3-n900.dtb: lp5523@32: 'enable-gpios' does not match any of the regexes: '^led@[0-8]$', '^multi-led@[0-8]$', 'pinctrl-[0-9]+'

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221127204058.57111-4-krzysztof.kozlowski@linaro.org
Signed-off-by: Rob Herring <robh@kernel.org>