Add #address-cells and #size-cells for gsc@20 to fix below warning:
arch/arm64/boot/dts/freescale/imx8mm-venice-gw7901.dtb: gsc@20: '#address-cells' is a required propert
Signed-off-by: Frank Li <Frank.Li@nxp.com> Signed-off-by: Shawn Guo <shawnguo@kernel.org>