Do allow auditing of read(2) and write(2) system calls, by assigning
those system calls audit event identifiers AUE_READ and AUE_WRITE.
While auditing file-descriptor I/O is not required by the Common
Criteria, in practice this proves useful for both live and forensic
analysis.

NB: freebsd32 already assigns AUE_READ and AUE_WRITE to read(2) and
write(2).

MFC after: 3 days
Sponsored by: DARPA, AFRL