xen: remove redundant initialization of variable ret

After commit 9f51c05d ("pvcalls-front: Avoid
get_free_pages(GFP_KERNEL) under spinlock"), the variable ret is being
initialized with '-ENOMEM' that is meaningless. So remove it.
Signed-off-by: Jing Xiangfeng <jingxiangfeng@huawei.com>
Link: https://lore.kernel.org/r/20200919031702.32192-1-jingxiangfeng@huawei.comReviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

drivers/xen/pvcalls-front.c

@@ -371,7 +371,7 @@ static int alloc_active_ring(struct sock_mapping *map)
 static int create_active(struct sock_mapping *map, evtchn_port_t *evtchn)
 {
 	void *bytes;
-	int ret = -ENOMEM, irq = -1, i;
+	int ret, irq = -1, i;
 
 	*evtchn = 0;
 	init_waitqueue_head(&map->active.inflight_conn_req);