scsi: lpfc: Memory allocation error during driver start-up on power8

The driver fails to allocate command buffers in the routine
lpfc_new_scsi_buf_s4

There is an inconsistency between lpfc_mem_alloc(), where the
phba->lpfc_sg_dma_buf_pool is created, and lpfc_new_scsi_buf_s4(),
when we allocate a buffer from the pool and check the alignment.  The
alignment should be on a page boundary, based on LPFC_SLI3_BG_ENABLED in
sli3_options, for both cases.

Fix by explicitly tracking sli4 vs sli3 and BG options.  The result is that
phba->cfg_sg_dma_buf_size is now set correctly for SLI-4.

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>