[RISCV] Simplify RVPUnary tablegen class. NFC

imm field was unused. rs1 is already handled in RVInstIBase.

Author: topperc

llvm/lib/Target/RISCV/RISCVInstrInfoP.td

@@ -69,20 +69,15 @@ class RVPUnaryImm8<bits<8> funct8, string opcodestr>
 let hasSideEffects = 0, mayLoad = 0, mayStore = 0 in
 class RVPUnary<bits<3> f, string opcodestr, dag operands, string argstr>
     : RVInstIBase<0b010, OPC_OP_IMM_32, (outs GPR:$rd), operands, opcodestr, argstr> {
-  bits<5> imm;
-  bits<5> rs1;
-
   let Inst{31}    = 0b1;
   let Inst{30-28} = f;
   let Inst{27}    = 0b0;
-  let Inst{19-15} = rs1;
 }
 
 class RVPUnaryImm5<bits<3> f, string opcodestr>
     : RVPUnary<f, opcodestr, (ins GPR:$rs1, uimm5:$uimm5), "$rd, $rs1, $uimm5"> {
   bits<5> uimm5;
 
-  let imm = uimm5;
   let Inst{26-25} = 0b01;
   let Inst{24-20} = uimm5;
 }