scsi: elx: efct: Data structures and defines for hw operations

Start the population of the efct target mode driver.  The driver is
contained in the drivers/scsi/elx/efct subdirectory.

Create the efct directory and start population of the driver by adding
SLI-4 configuration parameters, data structures for configuring SLI-4
queues, converting from OS to SLI-4 IO requests, and handling async events.

Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Hannes Reinecke <[email protected]>
Reviewed-by: Daniel Wagner <[email protected]>
Co-developed-by: Ram Vegesna <[email protected]>
Signed-off-by: Ram Vegesna <[email protected]>
Signed-off-by: James Smart <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

Author: jsmart-gh