mkfs: mark this wrapper as DEPRECATED

mkfs: mark this wrapper as DEPRECATED

Theodore Ts'o:

 I'll add that I've never been convinced that the mkfs front end is all
 that useful.  It's probably better for people to explicitly run
 /sbin/mkfs.xfs, /sbin/mkfs.ext4, etc.., so you don't have to worry
 about which options get passed down to the file system specific mkfs
 program, and which ones are interpreted by /sbin/mkfs --- and I don't
 believe /sbin/mkfs adds enough (err, any?) value that using
 "/sbin/mkfs -t xxx" vs "/sbin/mkfs.xxx" makes any sense whatsoever.

... and I absolutely agree.

Reported-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Karel Zak <kzak@redhat.com>