scsi: zfcp: improve kdoc for return of zfcp_status_read_refill()

Complements

v2.6.35 commit 64deb6ef ("[SCSI] zfcp: Use status_read_buf_num
provided by FCP channel") which replaced the hardcoded 16 with a
variable value

Also complements already existing fixups for above commit

v2.6.35 commit 8d88cf3f ("[SCSI] zfcp: Update status read mempool")
v3.10   commit 9edf7d75 ("[SCSI] zfcp: status read buffers on first adapter open with link down")
Signed-off-by: Steffen Maier <maier@linux.ibm.com>
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/s390/scsi/zfcp_aux.c

@@ -264,10 +264,10 @@ static void zfcp_free_low_mem_buffers(struct zfcp_adapter *adapter)
  * zfcp_status_read_refill - refill the long running status_read_requests
  * @adapter: ptr to struct zfcp_adapter for which the buffers should be refilled
  *
- * Returns: 0 on success, 1 otherwise
- *
- * if there are 16 or more status_read requests missing an adapter_reopen
- * is triggered
+ * Return:
+ * * 0 on success meaning at least one status read is pending
+ * * 1 if posting failed and not a single status read buffer is pending,
+ *     also triggers adapter reopen recovery
  */
 int zfcp_status_read_refill(struct zfcp_adapter *adapter)
 {