[libata] struct pci_dev related cleanups

* remove pointless pci_dev_to_dev() wrapper.  Just directly reference
  the embedded struct device like everyone else does.

* pata_cs5520: delete cs5520_remove_one(), it was a duplicate of
  ata_pci_remove_one()

* linux/libata.h: don't bother including linux/pci.h, we don't need it.
  Simply declare 'struct pci_dev' and assume interested parties will
  include the header, as they should be doing anyway.

* linux/libata.h: consolidate all CONFIG_PCI declarations into a
  single location in the header.

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index ce8ccb4..b05384a 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -7007,7 +7007,7 @@
  */
 void ata_pci_remove_one(struct pci_dev *pdev)
 {
-	struct device *dev = pci_dev_to_dev(pdev);
+	struct device *dev = &pdev->dev;
 	struct ata_host *host = dev_get_drvdata(dev);
 
 	ata_host_detach(host);