ftrace: Remove freelist from struct dyn_ftrace

ftrace: Remove freelist from struct dyn_ftrace

The 'freelist' member was introduced to 'struct dyn_ftrace' in commit
ee000b7f9fe429d2470c674ccec8d344f6789e0d (tracing: use union for
multi-usages field), but the use of this member was later removed in
3208230983a0ee3d95be22d463257e530c684956 (ftrace: Remove usage of
"freed" records). Remove also the 'freelist' member now.

Link: http://lkml.kernel.org/r/1393268401-24379-5-git-send-email-jslaby@suse.cz
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>