ARM: dts: rockchip: Enable GPU for XPI-3128

Add the supply and enable gpu node for XPI-3128 board.

Signed-off-by: Alex Bee <knaerzche@gmail.com>
Link: https://lore.kernel.org/r/20231204153547.97877-4-knaerzche@gmail.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>