MIPS: Restore Au1300 support

The Au1300, at least the one I have to test, uses the NetLogic vendor
ID, but commit 95b8a5e0 ("MIPS: Remove NETLOGIC support") also
dropped Au1300 detection.  Restore Au1300 detection.

Tested on DB1300 with Au1380 chip.

Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>