perf-top: Show the percentage of successfull PEBS-fixups

Use the PERF_RECORD_MISC_EXACT information to measure the success rate of
the PEBS fix-up.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: paulus@samba.org
Cc: eranian@google.com
Cc: robert.richter@amd.com
Cc: fweisbec@gmail.com
LKML-Reference: <20100304140100.694233760@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>