Commit 6750226e6d bumped the base MRF to
m2 instead of m0, but failed to adjust inst->mlen, which was being set
to the highest MRF. Subtracting the base MRF solves the issue.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>