dt-bindings: input: use generic node names

Devicetree specification expects nodes to have generic names, if
possible, so replace custom ones with something generic.  For gpio-keys,
the more popular format is "key-xxx" instead of "xxx-key", so choose the
first one.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Jeff LaBundy <jeff@labundy.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220524093136.7980-1-krzysztof.kozlowski@linaro.org


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>