scsi: scsi_transport_fc: Add kernel-doc for function return

Add function return value to prevent a kernel-doc warning:

scsi_transport_fc.h:780: warning: No description found for return value of 'fc_remote_port_chkready'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20240408025425.18778-8-rdunlap@infradead.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>