vhost: remove set but not used variable 'status'

Fix the following gcc warning:
drivers/vhost/vdpa.c:299:5: warning: variable 'status' set but not used [-Wunused-but-set-variable]
  u8 status;
     ^~~~~~
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NJason Yan <yanaijie@huawei.com>
Link: https://lore.kernel.org/r/20200402065106.20108-1-yanaijie@huawei.comSigned-off-by: NMichael S. Tsirkin <mst@redhat.com>

drivers/vhost/vdpa.c

@@ -296,7 +296,6 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
 	struct vdpa_callback cb;
 	struct vhost_virtqueue *vq;
 	struct vhost_vring_state s;
-	u8 status;
 	u32 idx;
 	long r;
 
@@ -310,8 +309,6 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
 	idx = array_index_nospec(idx, v->nvqs);
 	vq = &v->vqs[idx];
 
-	status = ops->get_status(vdpa);
-
 	if (cmd == VHOST_VDPA_SET_VRING_ENABLE) {
 		if (copy_from_user(&s, argp, sizeof(s)))
 			return -EFAULT;