[AMDGPU] Remove redundant field from DPP8 def

[Joe_Nash]

Summary

These lines set the value to what it already was,
so they are redundant. NFC

llvm/lib/Target/AMDGPU/VOP1Instructions.td

class VOP1_DPP8<bits<8> op, VOP1_Pseudo ps, VOPProfile p = ps.Pfl> :
   let SchedRW = ps.SchedRW;
   let Uses = ps.Uses;
 
   bits<8> vdst;
   let Inst{8-0}   = fi;
   let Inst{16-9}  = op;
   let Inst{24-17} = !if(p.EmitDst, vdst{7-0}, 0);
   let Inst{31-25} = 0x3f;
-
-  let AssemblerPredicate = HasDPP8;
-  let SubtargetPredicate = HasDPP8;
 }
 
 //===----------------------------------------------------------------------===//
 // GFX10.
 //===----------------------------------------------------------------------===//
 
 let AssemblerPredicate = isGFX10Plus, DecoderNamespace = "GFX10" in {
   multiclass VOP1Only_Real_gfx10<bits<9> op> {

llvm/lib/Target/AMDGPU/VOP2Instructions.td

class VOP2_DPP8<bits<6> op, VOP2_Pseudo ps,
   bits<8> src1;
 
   let Inst{8-0}   = fi;
   let Inst{16-9}  = !if(p.HasSrc1, src1{7-0}, 0);
   let Inst{24-17} = !if(p.EmitDst, vdst{7-0}, 0);
   let Inst{30-25} = op;
   let Inst{31}    = 0x0;
 
-  let AssemblerPredicate = HasDPP8;
-  let SubtargetPredicate = HasDPP8;
   let OtherPredicates = ps.OtherPredicates;
 }
 
 //===----------------------------------------------------------------------===//
 // GFX10.
 //===----------------------------------------------------------------------===//
 
 let AssemblerPredicate = isGFX10Plus, DecoderNamespace = "GFX10" in {