vhost: remove unused include

vhost.c does not need to know about sockets,
don't include sock.h
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vhost/vhost.c

@@ -30,8 +30,6 @@
 #include <linux/if_packet.h>
 #include <linux/if_arp.h>
 
-#include <net/sock.h>
-
 #include "vhost.h"
 
 enum {