scsi: lpfc: use pci_irq_alloc_vectors and pci_irq_free_vectors

This avoids having to store the msix_entries array and simpliefies the
shutdown and cleanup path a lot.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>