scsi: lpfc: Add description for lpfc_release_rpi()'s 'ndlpl param

scsi: lpfc: Add description for lpfc_release_rpi()'s 'ndlpl param

Fixes the following W=1 kernel build warning(s):

 drivers/scsi/lpfc/lpfc_nportdisc.c:1079: warning: Function parameter or member 'ndlp' not described in 'lpfc_release_rpi'

Link: https://lore.kernel.org/r/20200723122446.1329773-20-lee.jones@linaro.org
Cc: James Smart <james.smart@broadcom.com>
Cc: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>