sysutils/u-boot-*: Update to 2020.10

This also add two patches :

• The first one is for rockpro64, a commit upstream made the spi flash not detected anymore. The issue is still discussed with upstream so for now add a local patch.
• The second disabled shutting down usb controllers when calling efi_exit_boot_service. It somehow make u-boot hang but only when doing netboot and of course only on some boards so it's a weird issue. This is also a local patch for now as I still need to look deeper.