Add description of -P option to man pages

Add description of -P option to radtest and radclient man pages.

man/man1/radclient.1

@@ -95,6 +95,9 @@ requests to time out), before sending any more packets.
 
 This option permits you to discover the maximum load accepted by a
 RADIUS server.
+.IP "\-P\ \fIproto\fP"
+Use \fIproto\fP transport protocol ("tcp" or "udp").
+Only available if FreeRADIUS is compiled with TCP transport support.
 .IP \-q
 Go to quiet mode, and do not print out anything.
 .IP \-r\ \fInum_retries\fP

man/man1/radtest.1

@@ -28,6 +28,10 @@ way to test a radius server.
 The directory that contains the RADIUS dictionary files. Defaults to
 \fI/etc/raddb\fP.
 
+.IP "\-P\ \fIproto\fP"
+Use \fIproto\fP transport protocol ("tcp" or "udp").
+Only available if FreeRADIUS is compiled with TCP transport support.
+
 .IP "\-t \fIpap/chap/mschap/eap-md5\fP"
 Choose the authentiction method to use.  e.g. "-t pap", "-t chap", "-t
 mschap", or "-t eap-md5",.  Defaults to "pap".  Using EAP-MD5 requires