perf header: Swap pmu mapping numbers if needed

perf header: Swap pmu mapping numbers if needed

Like others, the numbers can be saved in a different endian format than
a host machine.  Swap them if needed.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Link: http://lkml.kernel.org/r/1346821373-31621-4-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>