[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/platforms/maple/setup.c b/arch/powerpc/platforms/maple/setup.c
index 9389d29..f21add0 100644
--- a/arch/powerpc/platforms/maple/setup.c
+++ b/arch/powerpc/platforms/maple/setup.c
@@ -248,7 +248,7 @@
 
 	/* Find address list in /platform-open-pic */
 	root = of_find_node_by_path("/");
-	naddr = prom_n_addr_cells(root);
+	naddr = of_n_addr_cells(root);
 	opprop = get_property(root, "platform-open-pic", &opplen);
 	if (opprop != 0) {
 		openpic_addr = of_read_number(opprop, naddr);