powerpc/pci: Make pci_read_irq_line() static

It's only used inside the same file where it's defined. There's
also no point exporting it anymore.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/pci.h

@@ -184,8 +184,6 @@ extern void of_scan_pci_bridge(struct pci_dev *dev);
 extern void of_scan_bus(struct device_node *node, struct pci_bus *bus);
 extern void of_rescan_bus(struct device_node *node, struct pci_bus *bus);
 
-extern int pci_read_irq_line(struct pci_dev *dev);
-
 struct file;
 extern pgprot_t	pci_phys_mem_access_prot(struct file *file,
 					 unsigned long pfn,

arch/powerpc/kernel/pci-common.c

@@ -214,7 +214,7 @@ char __devinit *pcibios_setup(char *str)
  * If the interrupt is used, then gets the interrupt line from the
  * openfirmware and sets it in the pci_dev and pci_config line.
  */
-int pci_read_irq_line(struct pci_dev *pci_dev)
+static int pci_read_irq_line(struct pci_dev *pci_dev)
 {
 	struct of_irq oirq;
 	unsigned int virq;
@@ -283,7 +283,6 @@ int pci_read_irq_line(struct pci_dev *pci_dev)
 
 	return 0;
 }
-EXPORT_SYMBOL(pci_read_irq_line);
 
 /*
  * Platform support for /proc/bus/pci/X/Y mmap()s,