scsi: scsi_transport_fc: Add an additional flag to fc_host_fpin_rcv()

scsi: scsi_transport_fc: Add an additional flag to fc_host_fpin_rcv()

The LLDD and the stack currently process FPINs received from the fabric,
but the stack is not aware of any action taken by the driver to alleviate
congestion. The current interface between the driver and the SCSI stack is
limited to passing the notification mainly for statistics and heuristics.

The reaction to an FPIN could be handled either by the driver or by the
stack (marginal path and failover). Amend the interface to indicate if
action on an FPIN has already been reacted to by the LLDDs or not. Add an
additional flag to fc_host_fpin_rcv() to indicate if the FPIN has been
acknowledged/reacted to by the driver.

Also added a new event code FCH_EVT_LINK_FPIN_ACK to notify to the user
that the event has been acknowledged/reacted by the LLDD driver

Link: https://lore.kernel.org/r/20230209034326.882514-1-muneendra.kumar@broadcom.com
Co-developed-by: Anil Gurumurthy <agurumurthy@marvell.com>
Signed-off-by: Anil Gurumurthy <agurumurthy@marvell.com>
Co-developed-by: Nilesh Javali <njavali@marvell.com>
Signed-off-by: Nilesh Javali <njavali@marvell.com>
Signed-off-by: Muneendra <muneendra.kumar@broadcom.com>
Reviewed-by: James Smart <jsmart2021@gmail.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>