arm64: dts: ti: Align gpio-key node names with dtschema

The node names should be generic and DT schema expects certain pattern
(e.g. with key/button/switch).

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Nishanth Menon <nm@ti.com>
Link: https://lore.kernel.org/r/20220616005333.18491-29-krzysztof.kozlowski@linaro.org