scsi: scsi_transport_fc: Allow setting rport state to current state

The only input fc_rport_set_marginal_state() currently accepts is
"Marginal" when port_state is "Online", and "Online" when the port_state
is "Marginal". It should also allow setting port_state to its current
state, either "Marginal or "Online".

Signed-off-by: Benjamin Marzinski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Ewan D. Milne <[e-mail]>
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/scsi/scsi_transport_fc.c

···
 		 */
 		if (rport->port_state == FC_PORTSTATE_ONLINE)
 			rport->port_state = port_state;
-		else
+		else if (port_state != rport->port_state)
 			return -EINVAL;
 	} else if (port_state == FC_PORTSTATE_ONLINE) {
 		/*
···
 		 */
 		if (rport->port_state == FC_PORTSTATE_MARGINAL)
 			rport->port_state = port_state;
-		else
+		else if (port_state != rport->port_state)
 			return -EINVAL;
 	} else
 		return -EINVAL;