The driver is currently using SLI-4 WQE templates only for NVMe.  Refactor
the template and the placement of the service routine so that it can be
used by both SCSI and NVMe.

Link: https://lore.kernel.org/r/20201115192646.12977-12-james.smart@broadcom.comCo-developed-by: NDick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: NDick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: NJames Smart <james.smart@broadcom.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>