arm64: dts: renesas: r9a09g047e57-smarc: Add gpio keys

arm64: dts: renesas: r9a09g047e57-smarc: Add gpio keys

RZ/G3E SMARC EVK  has 3 user buttons called USER_SW1, USER_SW2 and
USER_SW3 and SLEEP button with NMI support. Add a DT node in device tree
to instantiate the gpio-keys driver for these buttons.

The system can enter into STR state by pressing the sleep button and
wakeup from STR is done by pressing power button. The USER_SW{1,2,3}
configured as wakeup-source, so it can wakeup the system during s2idle.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/20250702092755.70847-1-biju.das.jz@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>