base,cpu,dev: Simplify ListenSocket::listen().

Remove the "reuse" parameter which default to true and was always
also explicitly set to true. Tidy up the code itself slightly, mostly
by using "panic_if" to remove some nesting.

Change-Id: Ie23971aabf2fe4252d27f1887468360722a72379
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/69159
Maintainer: Gabe Black <gabeblack@google.com>
Reviewed-by: Yu-hsin Wang <yuhsingw@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/dev/net/ethertap.cc

@@ -259,7 +259,7 @@ class TapListener
 void
 TapListener::listen()
 {
-    while (!listener.listen(port, true)) {
+    while (!listener.listen(port)) {
         DPRINTF(Ethernet, "TapListener(listen): Can't bind port %d\n", port);
         port++;
     }

src/dev/serial/terminal.cc

@@ -175,7 +175,7 @@ Terminal::listen(int port)
         return;
     }
 
-    while (!listener.listen(port, true)) {
+    while (!listener.listen(port)) {
         DPRINTF(Terminal,
                 ": can't bind address terminal port %d inuse PID %d\n",
                 port, getpid());