[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_32.c b/arch/powerpc/kernel/pci_32.c
index d8ef2e1..ecc7658 100644
--- a/arch/powerpc/kernel/pci_32.c
+++ b/arch/powerpc/kernel/pci_32.c
@@ -895,7 +895,7 @@
 	int rlen = 0, orig_rlen;
 	int memno = 0;
 	struct resource *res;
-	int np, na = prom_n_addr_cells(dev);
+	int np, na = of_n_addr_cells(dev);
 	np = na + 5;
 
 	/* First we try to merge ranges to fix a problem with some pmacs