[PATCH] init/do_mounts compilation warning fix

The compiler warns about about crd_load being defined but never used with
my config. The appended patch avoids compiling in the unused code in this
case.

init/do_mounts.c

@@ -840,7 +840,7 @@ void prepare_namespace(void)
 	mount_devfs_fs ();
 }
 
-#ifdef BUILD_CRAMDISK
+#if defined(BUILD_CRAMDISK) && defined(CONFIG_BLK_DEV_RAM)
 
 /*
  * gzip declarations
@@ -985,4 +985,4 @@ static int __init crd_load(int in_fd, int out_fd)
 	return result;
 }
 
-#endif  /* BUILD_CRAMDISK */
+#endif  /* BUILD_CRAMDISK && CONFIG_BLK_DEV_RAM */