ether_sprintf() used special format specifiers from BSD's printf(9).

http://www.unix.com/man-page/freebsd/9/printf/



Instead of re-implementing these specifiers in different ways and
because this method is not being used anywhere, it was completely
removed.

Signed-off-by: Or Cohen <orc@fewbytes.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>