findmnt: fix misleading warning messages for ntfs3

findmnt: fix misleading warning messages for ntfs3

* Remap fstab aliases like "ntfs3" to "ntfs" as reported by libblkid.

* Use mounttype (from --with-ntfs-mounttype=) to check if supported by
  the kernel rather than the type provided by libblkid.

* Don't check if the kernel supports type read from filesystem if an
  explicit type specified in fstab.

Fixes: https://github.com/util-linux/util-linux/issues/3912
Addresses: https://github.com/util-linux/util-linux/pull/3963
Signed-off-by: Karel Zak <kzak@redhat.com>