/boot/efi is used exclusively to mirror EFI contents to
other disks, as in `cp /boot/efi/EFI /boot/efis/disk{0,1,2}`
As shown in issue #256, this approach causes trouble with
`nixos-generate-config`, which fills filesystem type as 'none'.
This commit fixes this issue by removing /boot/efi mountpoint and
directly copy from '/boot/efis/primary-disk/EFI/'.
Closes#256
Signed-off-by: Maurice Zhou <jasper@apvc.uk>
11c527ed27