In both procdesc_kqops_event() and filt_proc(), the event variable can
have more than one bit set. This means that:
- We cannot compare it directly with NOTE_EXIT; we must binary-and them instead.
- We cannot binary-or it with the report mask; we must binary-and it with the request mask first.
MFC after: 1 week
Fixes: 2a5e58c59694 ("procdesc: add NOTE_PDSIGCHLD")
Fixes: b328975b9d7c ("procdesc: report NOTE_PDSIGCHLD for traced and stopped process")