slirp: Drop link_up checks from if_output and slirp_socket_can_recv

link_up is true once slirp is initialized, so these check are really not
required.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

slirp/if.c

@@ -138,10 +138,7 @@ diddit:
 	/*
 	 * This prevents us from malloc()ing too many mbufs
 	 */
-	if (link_up) {
-		/* if_start will check towrite */
-		if_start();
-	}
+	if_start();
 #endif
 }
 

slirp/slirp.c

@@ -824,9 +824,6 @@ size_t slirp_socket_can_recv(struct in_addr guest_addr, int guest_port)
 	struct iovec iov[2];
 	struct socket *so;
 
-    if (!link_up)
-        return 0;
-
 	so = slirp_find_ctl_socket(guest_addr, guest_port);
 
 	if (!so || so->so_state & SS_NOFDREF)