perf, tools, stat: Fix --no-scale

The -c option to enable multiplex scaling has been useless for quite some
time because scaling is default. It's only useful as --no-scale to
disable scaling. But the non scaling code path has bitrotted
and doesn't print anything because perf output code
relies on value run/ena information.

Also even when we don't want to scale a value it's still useful
to show its multiplex percentage.

This patch:
- Fixes help and documentation to show --no-scale instead of -c
- Removes -c, only keeps the long option because -c doesn't
support negatives.
- Enables running/enabled even with --no-scale
- And fixes some other problems in the no-scale output.

Before:

$ perf stat --no-scale -e cycles true

 Performance counter stats for 'true':

     <not counted>      cycles

       0.000984154 seconds time elapsed

After:

$ ./perf stat --no-scale -e cycles true

 Performance counter stats for 'true':

           706,070      cycles

       0.001219821 seconds time elapsed

Signed-off-by: Andi Kleen <ak@linux.intel.com>