perf bench numa: Fix cpumask memory leak in node_has_cpus()

perf bench numa: Fix cpumask memory leak in node_has_cpus()

Couple numa_allocate_cpumask() and numa_free_cpumask() functions

Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Balamuruhan S <bala24@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Link: http://lore.kernel.org/lkml/20200813113041.GA1685@oc3871087118.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>