qemu: Pull in u-boot submodule URL update#1019

stephanosio merged 4 commits intozephyrproject-rtos:mainzephyrproject-rtos/sdk-ng:mainfrom

stephanosio:qemu_uboot_prj_mirrorstephanosio/zephyr-sdk-ng:qemu_uboot_prj_mirrorCopy head branch name to clipboard