ftrace: remove function tracing from spinlock debug

The debug functions in spin_lock debugging pollute the output of the
function tracer. This patch adds the debug files in the lib director
to those that should not be compiled with mcount tracing.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>