scsi: lpfc: Replace PCI pool old API

The PCI pool API is deprecated. This commit replaces the PCI pool old
API by the appropriate function with the DMA pool API. It also updates
some comments, accordingly.

Signed-off-by: Romain Perier <romain.perier@collabora.com>
Reviewed-by: Peter Senna Tschudin <peter.senna@collabora.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>