Having noticed various bogus uses, I thought I'd go through and audit
them all. This is the result, with some other attributes also adjusted
as noticed in the process. (I think this tidying also is a good thing
to have ahead of APX further complicating insn length calculations.)
01: "prefix_extra" tidying
02: "sse4arg" adjustments
03: "ssemuladd" adjustments
04: "prefix_extra" can't really be "2"
05: replace/correct bogus "prefix_extra"
06: drop stray "prefix_extra"
07: add (adjust) XOP insn attributes
08: add missing "prefix" attribute to VF{,C}MULC
09: correct "length_immediate" in a few cases
10: drop redundant "prefix_data16" attributes
Jan
