The declaration of ftrace_set_func() is at the start of the ftrace.c file
and wrapped with a #ifdef CONFIG_FUNCTION_GRAPH condition. If function
graph tracing is enabled but CONFIG_DYNAMIC_FTRACE is not, a warning
about that function being declared static and unused is given.

This really should have been placed within the CONFIG_FUNCTION_GRAPH
condition that uses ftrace_set_func().

Moving the declaration down fixes the warning and makes the code cleaner.
Reported-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>