arm64: dts: renesas: r8a779a0: falcon-cpu: Add SW47-SW49 support

Add support for SW47, SW48 and SW49 via "gpio-keys" on the R-Car V3U
Falcon board.

Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Link: https://lore.kernel.org/r/20210922201314.3205674-1-kieran.bingham@ideasonboard.com


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>