ARM: dts: renesas: marzen: Rename keyboard nodes

ARM: dts: renesas: marzen: Rename keyboard nodes

make dtbs_check:

    arch/arm/boot/dts/renesas/r8a7779-marzen.dtb: /: keyboard-gpio: {'compatible': ['gpio-keys-polled'], 'poll-interval': [[50]], 'pinctrl-0': [[29]], 'pinctrl-names': ['default'], 'key-3': {'gpios': [[28, 19, 1]], 'linux,code': [[4]], 'label': ['SW1-3'], 'debounce-interval': [[20]]}, 'key-4': {'gpios': [[28, 20, 1]], 'linux,code': [[5]], 'label': ['SW1-4'], 'debounce-interval': [[20]]}} is not of type 'array'
	    from schema $id: http://devicetree.org/schemas/gpio/gpio-consumer.yaml#
    arch/arm/boot/dts/renesas/r8a7779-marzen.dtb: pinctrl@fffc0000: keyboard-gpio: {'pins': ['GP_0_19', 'GP_0_20'], 'bias-pull-up': True, 'phandle': [[29]]} is not of type 'array'
	    from schema $id: http://devicetree.org/schemas/gpio/gpio-consumer.yaml#

Node names ending in "-gpio" confuse the checker.
Fix this by renaming the keyboards to "keypad-0" and "keypad-1", as they
are not full keyboards.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/eec1ccfb75c6215428609fdcaf3a37c75fe1fc87.1698228163.git.geert+renesas@glider.be