Differentiate a EFI system partition being used as /boot 

Right now, chkboot doesn't check the underlying filesystem of the partition mounted at /boot. This introduces some problems when a EFI system partition is being used as /boot. Since the UEFI specification dictates it must be a FAT filesystem, we could check for this and treat it differently, specifically regarding inodes and extents. See: https://aur.archlinux.org/packages/chkboot/?comments=all
