scsi: fnic: Modify fnic interfaces to use FDLS

scsi: fnic: Modify fnic interfaces to use FDLS

Modify fnic driver interfaces to use FDLS and supporting functions.

Refactor code in fnic_probe and fnic_remove.

Get fnic from shost_priv.

Add error handling in stats processing functions.

Modify some print statements.

Add support to do module unload cleanup.

Use placeholder functions/modify function declarations to not break
compilation.

Reviewed-by: Sesidhar Baddela <sebaddel@cisco.com>
Reviewed-by: Arulprabhu Ponnusamy <arulponn@cisco.com>
Reviewed-by: Gian Carlo Boffa <gcboffa@cisco.com>
Co-developed-by: Arun Easi <aeasi@cisco.com>
Signed-off-by: Arun Easi <aeasi@cisco.com>
Co-developed-by: Karan Tilak Kumar <kartilak@cisco.com>
Signed-off-by: Karan Tilak Kumar <kartilak@cisco.com>
Link: https://lore.kernel.org/r/20241212020312.4786-12-kartilak@cisco.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>