perf record: Replace option --bpf-event with --no-bpf-event

Currently, monitoring of BPF programs through bpf_event is off by
default for 'perf record'.

To turn it on, the user need to use option "--bpf-event".  As BPF gets
wider adoption in different subsystems, this option becomes
inconvenient.

This patch makes bpf_event on by default, and adds option "--no-bpf-event"
to turn it off. Since option --bpf-event is not released yet, it is safe
to remove it.

Signed-off-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: kernel-team@fb.com
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislav Fomichev <sdf@google.com>
Link: http://lkml.kernel.org/r/20190312053051.2690567-2-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index b120e54..c59743d 100644
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -66,7 +66,7 @@
 	bool	     ignore_missing_thread;
 	bool	     strict_freq;
 	bool	     sample_id;
-	bool	     bpf_event;
+	bool	     no_bpf_event;
 	unsigned int freq;
 	unsigned int mmap_pages;
 	unsigned int auxtrace_mmap_pages;