Add power-supply for vxt,vl050-8048nt-c01 to fix below CHECK_DTBS warnings:
arch/arm/boot/dts/nxp/imx/imx6ul-pico-dwarf.dtb: panel (vxt,vl050-8048nt-c01): 'power-supply' is a required property
Signed-off-by: Frank Li <Frank.Li@nxp.com> Reviewed-by: Peng Fan <peng.fan@nxp.com> Signed-off-by: Shawn Guo <shawnguo@kernel.org>