ftrace: Do not test frame pointers if -mfentry is used

ftrace: Do not test frame pointers if -mfentry is used

The function graph has a test to check if the frame pointer is
corrupted, which can happen with various options of gcc with mcount.
But this is not an issue with -mfentry as -mfentry does not need nor use
frame pointers for function graph tracing.

Link: http://lkml.kernel.org/r/[email protected]
Acked-by: H. Peter Anvin <[email protected]>
Acked-by: Ingo Molnar <[email protected]>
Cc: Andi Kleen <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>