scsi: elx: libefc_sli: BMBX routines and SLI config commands

Add routines to create mailbox commands used during adapter initialization
and add APIs to issue mailbox commands to the adapter through the bootstrap
mailbox register.

Link: https://lore.kernel.org/r/20210601235512.20104-7-jsmart2021@gmail.comReviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Co-developed-by: Ram Vegesna <ram.vegesna@broadcom.com>
Signed-off-by: Ram Vegesna <ram.vegesna@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>