ftrace: Join functions ftrace_module_init() and ftrace_init_module()

Simple cleanup. No need for two functions here.
The whole work can simply be done inside 'ftrace_module_init'.

Link: http://lkml.kernel.org/r/1449067197-5718-1-git-send-email-abelvesa@linux.com



Signed-off-by: Abel Vesa <abelvesa@linux.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>