base: Fix forcing loopback only binding for listeners.

Despite online documentation, the type used for sin_addr.s_addr is not
actually an unsigned long, it is an in_addr_t. When an unsigned long is a 64
bit value, the endian conversion moves the relevant bits of the 32 bit
in_addr_t to positions which are truncated away. This forces the value to 0
which means to bind to any interface, the opposite of the intended effect.

Change-Id: I53c63dea6bd88144dfef1a9a49b478fab30a8ba2
Reviewed-on: https://gem5-review.googlesource.com/5301
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

src/base/socket.cc

@@ -106,7 +106,7 @@ ListenSocket::listen(int port, bool reuse)
     struct sockaddr_in sockaddr;
     sockaddr.sin_family = PF_INET;
     sockaddr.sin_addr.s_addr =
-        htobe<unsigned long>(bindToLoopback ? INADDR_LOOPBACK : INADDR_ANY);
+        htobe<in_addr_t>(bindToLoopback ? INADDR_LOOPBACK : INADDR_ANY);
     sockaddr.sin_port = htons(port);
     // finally clear sin_zero
     memset(&sockaddr.sin_zero, 0, sizeof(sockaddr.sin_zero));