[AVR][NFC] Remove unused instruction classes

[jacquesguan]

LGTM

llvm/lib/Target/AVR/AVRInstrFormats.td

class FRdRr<bits<4> opcode, bits<2> f, dag outs, dag ins, string asmstr,
 
   let Inst{15 - 12} = opcode;
   let Inst{11 - 10} = f;
   let Inst{9} = rr{4};
   let Inst{8 - 4} = rd;
   let Inst{3 - 0} = rr{3 - 0};
 }
 
-class FTST<bits<4> opcode, bits<2> f, dag outs, dag ins, string asmstr,
-           list<dag> pattern> : AVRInst16<outs, ins, asmstr, pattern> {
-  bits<5> rd;
-
-  let Inst{15 - 12} = opcode;
-  let Inst{11 - 10} = f;
-  let Inst{9} = rd{4};
-  let Inst{8 - 4} = rd;
-  let Inst{3 - 0} = rd{3 - 0};
-}
-
 //===----------------------------------------------------------------------===//
 // Instruction of the format `<mnemonic> Z, Rd`
 // <|1001|001r|rrrr|0ttt>
 //===----------------------------------------------------------------------===//
 class FZRd<bits<3> t, dag outs, dag ins, string asmstr, list<dag> pattern>
     : AVRInst16<outs, ins, asmstr, pattern> {
   bits<5> rd;
 

 // Special, opcode only instructions: <|opcode|>
 //===----------------------------------------------------------------------===//
 
 class F16<bits<16> opcode, dag outs, dag ins, string asmstr, list<dag> pattern>
     : AVRInst16<outs, ins, asmstr, pattern> {
   let Inst = opcode;
 }
 
-class F32<bits<32> opcode, dag outs, dag ins, string asmstr, list<dag> pattern>
-    : AVRInst32<outs, ins, asmstr, pattern> {
-  let Inst = opcode;
-}
-
 //===----------------------------------------------------------------------===//
 // Branching instructions with immediate12: <|110f|kkkk|kkkk|kkkk|>
 // f = secondary opcode = 1 bit
 // k = constant address = 12 bits
 //===----------------------------------------------------------------------===//
 class FBRk<bit f, dag outs, dag ins, string asmstr, list<dag> pattern>
     : AVRInst16<outs, ins, asmstr, pattern> {
   bits<12> k;