regulator: dt-bindings: fixed-regulator: allow gpios property

'gpios' is in general preferred even for single GPIO specifiers and
there are DTS boards using it (exynos4412-p4note.dtsi), so allow both
versions.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230120133010.299797-1-krzysztof.kozlowski@linaro.org


Signed-off-by: Mark Brown <broonie@kernel.org>