vhost/scsi: silence uninitialized variable warning

This is to silence an uninitialized variable warning in debug output.
The problem is this line:

	pr_debug("vhost_get_vq_desc: head: %d, out: %u in: %u\n",
		 head, out, in);

If "head == vq->num" is true on the first iteration then "out" and "in"
aren't initialized.  We handle that a few lines after the printk.  I was
tempted to just delete the pr_debug() but I decided to just initialize
them to zero instead.

Also checkpatch.pl complains if variables are declared as just
"unsigned" without the "int".

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>