ftrace: combine stack trace in function call

Impact: less likely to interleave function and stack traces

This patch does replaces the separate stack trace on function with
a record function and stack trace together. This will switch between
the function only recording to a function and stack recording.

Also some whitespace fix ups as well.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>