ftrace: Remove empty declaration ftrace_enable_daemon() and ftrace_disable_daemon()

The definition of ftrace_enable_daemon() and ftrace_disable_daemon() has
been removed since commit cb7be3b2 ("ftrace: remove daemon"), remain
the declarations in the header files, so remove it.

Link: https://lore.kernel.org/linux-trace-kernel/20230804013636.115940-1-zhangzekun11@huawei.com



Cc: <mhiramat@kernel.org>
Cc: <mark.rutland@arm.com>
Signed-off-by: Zhang Zekun <zhangzekun11@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>