MIPS: perf: Add support for OCTEON III perf events.

According to Hardware Reference Manual, OCTEON III
are mostly same as previous OCTEON models. So just
enable them and extend supported event code.
0x3e and 0x3f still reserved.

Signed-off-by: Jia Qingtong <jiaqingtong97@163.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>