After running gummiboot loader install option, the installed target
storage device boot parameter for root=PARTUUID is empty causing boot failure.
This issue is only observed with gummiboot and not with GRUB loader.
This fix assign the rootuuid of the rootfs partition for gummiboot loader.
[YOCTO #8709] Signed-off-by: Ng, Mei Yeen <mei.yeen.ng@intel.com> Signed-off-by: Ross Burton <ross.burton@intel.com>