PCI: Make pci_ats_init() private

This interface:

  void pci_ats_init(struct pci_dev *dev);

is only used in drivers/pci/ and does not need to be seen by the rest of
the kernel.  Move it to drivers/pci/pci.h so it's private to the PCI
subsystem.

Link: https://lore.kernel.org/r/20190724233848.73327-9-skunberg.kelsey@gmail.com
Signed-off-by: Kelsey Skunberg <skunberg.kelsey@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/pci.h

@@ -439,11 +439,12 @@ static inline void pci_restore_dpc_state(struct pci_dev *dev) {}
 #endif
 
 #ifdef CONFIG_PCI_ATS
+/* Address Translation Service */
+void pci_ats_init(struct pci_dev *dev);
 void pci_restore_ats_state(struct pci_dev *dev);
 #else
-static inline void pci_restore_ats_state(struct pci_dev *dev)
-{
-}
+static inline void pci_ats_init(struct pci_dev *d) { }
+static inline void pci_restore_ats_state(struct pci_dev *dev) { }
 #endif /* CONFIG_PCI_ATS */
 
 #ifdef CONFIG_PCI_IOV

include/linux/pci.h

@@ -1761,13 +1761,11 @@ static inline bool pci_ats_disabled(void) { return true; }
 
 #ifdef CONFIG_PCI_ATS
 /* Address Translation Service */
-void pci_ats_init(struct pci_dev *dev);
 int pci_enable_ats(struct pci_dev *dev, int ps);
 void pci_disable_ats(struct pci_dev *dev);
 int pci_ats_queue_depth(struct pci_dev *dev);
 int pci_ats_page_aligned(struct pci_dev *dev);
 #else
-static inline void pci_ats_init(struct pci_dev *d) { }
 static inline int pci_enable_ats(struct pci_dev *d, int ps) { return -ENODEV; }
 static inline void pci_disable_ats(struct pci_dev *d) { }
 static inline int pci_ats_queue_depth(struct pci_dev *d) { return -ENODEV; }