perf test bpf: Free obj_buf

ASan reports some memory leaks when running:

  # perf test "42: BPF filter"

The first of these leaks is caused by obj_buf never being deallocated in
__test__bpf.

This patch adds the missing free.

Signed-off-by: Riccardo Mancini <[email protected]>
Fixes: ba1fae4 ("perf test: Add 'perf test BPF'")
Cc: Ian Rogers <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lore.kernel.org/lkml/60f3ca935fe6672e7e866276ce6264c9e26e4c87.1626343282.git.rickyman7@gmail.com
[ Added missing stdlib.h include ]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: Manciukic

tools/perf/tests/bpf.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <errno.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <sys/epoll.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -276,6 +277,7 @@ static int __test__bpf(int idx)
 	}
 
 out:
+	free(obj_buf);
 	bpf__clear();
 	return ret;
 }