This series adds support for a number of more or less recently announced
ISA extensions. Plus a little bit of (more or less related) cleanup. The
series interacts mildly (and only contextually) with the AVX512-FP16 one.
Note that patch 1 was previously posted standalone; the posting here is
unchanged, so isn't called "v2". Note further that while the last patch
is kind of incomplete (it doesn't enable the feature for guest use), it
could still be applied ahead of further VMX-specific work that's needed
there (and that's dependent upon documentation becoming more complete).

Apart from contextual interaction the patches should be largely
independent of one another; only 5 strictly depends on 4.

1: support LKGS
2: support WRMSRNS
3: drop regs field from emulator state structure
4: support CMPccXADD
5: re-use new stub_exn field in state structure
6: support AVX-IFMA insns
7: support AVX-VNNI-INT8
8: support AVX-NE-CONVERT insns
9: support {RD,WR}MSRLIST

Jan