ARM: dts: exynos: drop unused pinctrl-names from Galaxy Tab

pinctrl-names without pinctrl-0 are simply unused:

  exynos5420-klimt-wifi.dtb: gpio-keys: 'pinctrl-0' is a dependency of 'pinctrl-names'

Link: https://lore.kernel.org/r/20221204190543.143986-2-krzysztof.kozlowski@linaro.org


Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>