Fix wrong comment.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 5e1967f..f75ab74 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -131,7 +131,7 @@
 		j = 0;
 	}
 }
-#endif /* CONFIG_64BIT */
+#endif /* CONFIG_32BIT */
 #endif /* CONFIG_HIGHMEM */
 
 #ifndef CONFIG_NEED_MULTIPLE_NODES