Switch the rest of the perf code to use libperf's perf_cpu_map__nr(),
which is the same as current cpu_map__nr() and remove the cpu_map__nr()
function.

Link: http://lkml.kernel.org/n/tip-6e0guy75clis7nm0xpuz9fga@git.kernel.orgSigned-off-by: NJiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190822111141.25823-3-jolsa@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>