Fix issues with ethernet in u-boot on rpi 3b+#1430

JakubSzczudlo wants to merge 2 commits intoagherzan:kirkstoneagherzan/meta-raspberrypi:kirkstonefrom

JakubSzczudlo:fix/rpi_3b_plus_uboot_ethernetJakubSzczudlo/meta-raspberrypi:fix/rpi_3b_plus_uboot_ethernetCopy head branch name to clipboard