Define a bit for MXU in insn_flags. This is the first non-MIPS
(third party) ASE supported in QEMU for MIPS, so it is placed in
the section "bits 56-63: vendor-specific ASEs".
Reviewed-by: NAleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: NCraig Janeczek <jancraig@amazon.com>
Signed-off-by: NAleksandar Markovic <amarkovic@wavecomp.com>