slirp: Drop redundant checks from slirp_output

Slirp doesn't invoke slirp[_can]_output before it is initialized. The
motivation for these checks (3b7f5d479c) no longer applies. So drop
them.

Note: slirp_vc will become invalid if the slirp stack is removed during
runtime. But this is no new bug and will be fixed later.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

net.c

diff --git a/net.c b/net.c
index 5f8edda..70cc995 100644
--- a/net.c
+++ b/net.c
@@ -696,7 +696,7 @@
 
 int slirp_can_output(void)
 {
-    return !slirp_vc || qemu_can_send_packet(slirp_vc);
+    return qemu_can_send_packet(slirp_vc);
 }
 
 void slirp_output(const uint8_t *pkt, int pkt_len)
@@ -705,8 +705,6 @@
     printf("slirp output:\n");
     hex_dump(stdout, pkt, pkt_len);
 #endif
-    if (!slirp_vc)
-        return;
     qemu_send_packet(slirp_vc, pkt, pkt_len);
 }