mips: Need to set replace_xxx in irarch now
mips: Need to set replace_xxx in irarch now

Hopefully this fixes the fallout from acf1a376620890041b2a637a79a46da6700012d6

MatzeB/libfirm,MatzeB/libfirm,libfirm/libfirm,MatzeB/libfirm,libfirm/libfirm,MatzeB/libfirm,libfirm/libfirm,MatzeB/libfirm,MatzeB/libfirm,MatzeB/libfirm,libfirm/libfirm,libfirm/libfirm