vringh: fix a typo in comments for vringh_kiov

Probably it is a simple copy error from struct vring_iov.

Signed-off-by: Shunsuke Mie <mie@igel.co.jp>
Message-Id: <20230202104248.2040652-1-mie@igel.co.jp>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

include/linux/vringh.h

@@ -92,7 +92,7 @@ struct vringh_iov {
 };
 
 /**
- * struct vringh_iov - kvec mangler.
+ * struct vringh_kiov - kvec mangler.
  *
  * Mangles kvec in place, and restores it.
  * Remaining data is iov + i, of used - i elements.