ping: Remove a vestigial notdef

It was once a function on 4.3BSD, pr_type() [1], used to convert an ICMP
"type" field to a printable string.  In 4.4BSD it was superseded by
pr_icmph() [2].

NetBSD [3] and OpenBSD [4] have already removed it.

[1]: https://minnie.tuhs.org/cgi-bin/utree.pl?file=4.3BSD/usr/src/etc/ping.c
[2]: https://minnie.tuhs.org/cgi-bin/utree.pl?file=4.4BSD/usr/src/sbin/ping/ping.c
[3]: 203dfd3486
[4]: 9bbbbbb75d

Reviewed by:	markj
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D37247

sbin/ping/ping.c

@@ -1484,22 +1484,6 @@ finish(void)
 		exit(2);
 }
 
-#ifdef notdef
-static char *ttab[] = {
-	"Echo Reply",		/* ip + seq + udata */
-	"Dest Unreachable",	/* net, host, proto, port, frag, sr + IP */
-	"Source Quench",	/* IP */
-	"Redirect",		/* redirect type, gateway, + IP  */
-	"Echo",
-	"Time Exceeded",	/* transit, frag reassem + IP */
-	"Parameter Problem",	/* pointer + IP */
-	"Timestamp",		/* id + seq + three timestamps */
-	"Timestamp Reply",	/* " */
-	"Info Request",		/* id + sq */
-	"Info Reply"		/* " */
-};
-#endif
-
 /*
  * pr_icmph --
  *	Print a descriptive string about an ICMP header.