perf jit: Let jit_process() return errors

In preparation for moving clockid validation into jit_process().

Previously a return value of zero meant the processing had been done and
non-zero meant either the processing was not done (i.e. not the jitdump
file mmap event) or an error occurred.

Change it so that zero means the processing was not done, one means the
processing was done and successful, and negative values are an error.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1457005856-6143-5-git-send-email-adrian.hunter@intel.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>