scsi: lpfc: Refactor WQE structure definitions for common use

In preparation of reworking the driver to use a native SLI-4 WQE interface
for the SCSI and NVMe I/O paths, start by commonizing the WQE exchange type
and command type attributes.

While adjusting these options also noted the variance in the pbde field.
Fix this by setting templates to 0 and in NVMe, which explicitly uses this
option, setting the value.

Link: https://lore.kernel.org/r/20201115192646.12977-11-james.smart@broadcom.com


Co-developed-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>