dt-bindings: arm: sunxi: document RerVision A33-Vstar board

RerVision A33-Vstar is an evaluation board of their A33-Core1 SoM.

Add its compatible (with the SoM compatible) to the sunxi board DT
binding file.

Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20240913104845.4112986-1-uwu@icenowy.me


Signed-off-by: Chen-Yu Tsai <wens@csie.org>