[SCSI] be2iscsi: Fix Task Completion Event handling

The completion events returned by adapter differs based on the
adapter. This fix checks for the adapter type and process the
completion event.

Signed-off-by: John Soni Jose <sony.john-n@emulex.com>
Signed-off-by: Jayamohan Kallickal <jayamohan.kallickal@emulex.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>