x86: don't show suffixes for to-scalar-int conversion insns

x86: don't show suffixes for to-scalar-int conversion insns

In the course of folding their patterns (possible now that the pointless
and partly even bogus VecESize are no longer in the way) I've noticed
that vcvt*2usi, other than their vcvt*2si counterparts, don't allow for
any suffixes. As that is supposedly intentional, make the disassembler
consistently omit suffixes for all to-scalar-int conversion insns.