net: don't set native endianness

commit 5be7d9f1
    vhost-net: tell tap backend about the vnet endianness
makes vhost net always try to set LE - even if that matches the
native endian-ness.

This makes it fail on older kernels on x86 without TUNSETVNETLE support.

To fix, make qemu_set_vnet_le/qemu_set_vnet_be skip the
ioctl if it matches the host endian-ness.
Reported-by: NMarcel Apfelbaum <marcel@redhat.com>
Cc: Greg Kurz <gkurz@linux.vnet.ibm.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NMarcel Apfelbaum <marcel@redhat.com>

net/net.c

@@ -524,20 +524,28 @@ void qemu_set_vnet_hdr_len(NetClientState *nc, int len)
 
 int qemu_set_vnet_le(NetClientState *nc, bool is_le)
 {
+#ifdef HOST_WORDS_BIGENDIAN
     if (!nc || !nc->info->set_vnet_le) {
         return -ENOSYS;
     }
 
     return nc->info->set_vnet_le(nc, is_le);
+#else
+    return 0;
+#endif
 }
 
 int qemu_set_vnet_be(NetClientState *nc, bool is_be)
 {
+#ifdef HOST_WORDS_BIGENDIAN
+    return 0;
+#else
     if (!nc || !nc->info->set_vnet_be) {
         return -ENOSYS;
     }
 
     return nc->info->set_vnet_be(nc, is_be);
+#endif
 }
 
 int qemu_can_send_packet(NetClientState *sender)