Remove incorrect references to multicast from -B documentation.

(This is partially because iperf3 doesn't do multicast, yet.)

Also it's not specifically a client-side option, so relocate it in
the manpage.

src/iperf3.1

@@ -46,6 +46,9 @@ Note that when using this feature, a process will only be bound
 to a single CPU (as opposed to a set containing potentialy multiple
 CPUs).
 .TP
+.BR -B ", " --bind " \fIhost\fR"
+bind to a specific interface
+.TP
 .BR -V ", " --verbose " "
 give more detailed output 
 .TP
@@ -114,9 +117,6 @@ run in reverse mode (server sends, client receives)
 .BR -w ", " --window " \fIn\fR[KM]"
 TCP window size / socket buffer size (this gets sent to the server and used on that side too)
 .TP
-.BR -B ", " --bind " \fIn\fR[KM]"
-bind to a specific interface or multicast address
-.TP
 .BR -M ", " --set-mss " \fIn\fR"
 set TCP maximum segment size (MTU - 40 bytes)
 .TP

src/locale.c

@@ -102,7 +102,7 @@ const char usage_longstr[] = "Usage: iperf [-s|-c host] [options]\n"
                            "  -P, --parallel  #         number of parallel client streams to run\n"
                            "  -R, --reverse             run in reverse mode (server sends, client receives)\n"
                            "  -w, --window    #[KMG]    TCP window size (socket buffer size)\n"
-                           "  -B, --bind      <host>    bind to a specific interface or multicast address\n"
+                           "  -B, --bind      <host>    bind to a specific interface\n"
 #if defined(linux)
                            "  -C, --linux-congestion <algo>  set TCP congestion control algorithm (Linux only)\n"
 #endif