Launch the boot tracing inside the initcall_debug area. Old printk
have not been removed to keep the old way of initcall tracing for
backward compatibility.

[ mingo@elte.hu: resolved conflicts ]
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>