My previous patch (r84124) for setting the encoding bits 4 and 7 of DPSoRegFrm

My previous patch (r84124) for setting the encoding bits 4 and 7 of DPSoRegFrm
was wrong and too aggressive in the sense that DPSoRegFrm includes both constant
shifts (with Inst{4} = 0) and register controlled shifts (with Inst{4} = 1 and
Inst{7} = 0).  The 'rr' fragment of the multiclass definitions actually means
register/register with no shift, see A8-11.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86319 91177308-0d34-0410-b5e6-96231b3b80d8