rockchip: rv1126: Migrate to OF_UPSTREAM

Migrate RV1126 boards that exists in Linux v6.8 to use OF_UPSTREAM.

Following targets is migrated to use OF_UPSTREAM:

- rv1126-edgeble-neu2 : Board is an industrial form factor
                        IO board.
- sonoff-ihost-rv1126 : Gateway device designed to provide a
                        Smart Home Hub.

Cc: Tim Lunn <tim@feathertop.org>
Cc: Jagan Teki <jagan@edgeble.ai>
Reviewed-By: Tim Lunn <tim@feathertop.org>
Tested-By: Tim Lunn <tim@feathertop.org>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Signed-off-by: Anand Moon <anand@edgeble.ai>
Signed-off-by: Anand Moon <linux.amoon@gmail.com>