[POWERPC] Rename prom_n_addr_cells to of_n_addr_cells

This is more consistent and gets us closer to the Sparc code.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/kernel/pci_64.c b/arch/powerpc/kernel/pci_64.c
index db1d40e..84b4f66 100644
--- a/arch/powerpc/kernel/pci_64.c
+++ b/arch/powerpc/kernel/pci_64.c
@@ -957,7 +957,7 @@
 	int rlen = 0;
 	int memno = 0;
 	struct resource *res;
-	int np, na = prom_n_addr_cells(dev);
+	int np, na = of_n_addr_cells(dev);
 	unsigned long pci_addr, cpu_phys_addr;
 
 	np = na + 5;