Throw RI for invalid MFMC0-class instructions. Introduce optional
MIPS_STRICT_STANDARD define to adhere more to the spec than it makes
sense in normal operation.


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@2650 c046a42c-6fe2-441c-8c8c-71466251a162
