arch/arm/kernel/ftrace.c references mcount like kernel/tracing/ftrace.c,
so change the exclusion filter to match any ftrace.o.

Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>