When booting on UEFI, there was an issue mounting the vfat
filesystem. It was caused because the mount was defined in
/etc/fstab in lowercase, but the disk had it labeled in upper
case, and system could not find it. Conver the label to upper
case in case of fat/vfat.
Change-Id: Id3dee735e6f8fb221d199c4aba648f3e9a6e4206