ARM: 8940/1: ftrace: remove mcount(),ftrace_caller_old() and ftrace_call_old()

Commit d3c61619 ("ARM: 8788/1: ftrace: remove old mcount support")
removed the old mcount support, but forget to remove these three
declarations. This patch removes them.

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>