tracing: consolidate code between trace_output.c and trace_function_graph.c

Both trace_output.c and trace_function_graph.c do basically the same
thing to handle the printing of the latency-format. This patch moves
the code into one function that both can use.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --cc kernel/trace/trace_functions_graph.c
Simple merge

diff --cc kernel/trace/trace_output.c
Simple merge

diff --cc kernel/trace/trace_output.h
Simple merge