perf: Fix opt help text for --no-bpf-event

The opt name was once inverted but the help text didn't reflect the
change.

Fixes: 71184c6a ("perf record: Replace option --bpf-event with --no-bpf-event")
Signed-off-by: Fam Zheng <famzheng@amazon.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>