PCI: Move informational printk to pci_add_dma_alias()

One of the quirks that adds DMA aliases logs an informational message in
dmesg.  Move that to pci_add_dma_alias() so all users log the message
consistently.  No functional change intended (except extra message).

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>