arm64: dts: rockchip: make use gpio-keys for buttons on puma-haikou

arm64: dts: rockchip: make use gpio-keys for buttons on puma-haikou

Haikou is an evaluation and development platform for System on
Modules (SOMs).

Haikou devkit exposes multiple buttons so let's register them as
such so that the input subsystem can generate events when pressed or
switched.

Signed-off-by: Vahe Grigoryan <vahe.grigoryan@theobroma-systems.com>
Link: https://lore.kernel.org/r/20231214122801.3144180-3-vahe.grigoryan@theobroma-systems.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>