[MIPS] Rewrite all the assembler interrupt handlers to C.
Saves like 1,600 lines of code, is way easier to debug, compilers frequently do a better job than the cut and paste type of handlers many boards had. And finally having all the stuff done in a single place also means alot of bug potencial for the MT ASE is gone. The only surviving handler in assembler is the DECstation one; I hope Maciej will rewrite it. Signed-off-by: Ralf Baechle <email@example.com>