perf tools: Fix perf.data format description of NRCPUS header

In the perf.data HEADER_CPUDESC feadure header we store first the number
of available CPUs in the system, then the number of CPUs at the time of
writing the header, not the other way around.

Reported-by: Thomas-Mich Richter <[email protected]>
Acked-by: Andi Kleen <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: He Kuang <[email protected]>
Cc: Hendrik Brueckner <[email protected]>
Cc: Jin Yao <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kim Phillips <[email protected]>
Cc: Lakshman Annadorai <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Simon Que <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Wang Nan <[email protected]>
Link: https://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: acmel

tools/perf/Documentation/perf.data-file-format.txt

@@ -111,8 +111,8 @@ A perf_header_string with the CPU architecture (uname -m)
 A structure defining the number of CPUs.
 
 struct nr_cpus {
-       uint32_t nr_cpus_online;
        uint32_t nr_cpus_available; /* CPUs not yet onlined */
+       uint32_t nr_cpus_online;
 };
 
 	HEADER_CPUDESC = 8,