s390/qeth: update kerneldoc for qeth_add_hw_header()

qeth_add_hw_header() is missing documentation for some of its
parameters, fix that up.
Reported-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/s390/net/qeth_core_main.c

@@ -3873,12 +3873,14 @@ static unsigned int qeth_count_elements(struct sk_buff *skb,
 
 /**
  * qeth_add_hw_header() - add a HW header to an skb.
+ * @queue: TX queue that the skb will be placed on.
  * @skb: skb that the HW header should be added to.
  * @hdr: double pointer to a qeth_hdr. When returning with >= 0,
  *	 it contains a valid pointer to a qeth_hdr.
  * @hdr_len: length of the HW header.
  * @proto_len: length of protocol headers that need to be in same page as the
  *	       HW header.
+ * @elements: returns the required number of buffer elements for this skb.
  *
  * Returns the pushed length. If the header can't be pushed on
  * (eg. because it would cross a page boundary), it is allocated from