[LLVM][NVPTX] Remove nonexistent ftz ops (llvm#106100)

According to the PTX
[spec](https://docs.nvidia.com/cuda/parallel-thread-execution/#half-precision-floating-point-instructions-max),
max & min instructions do not support the `ftz` modifier for `bf16` &
`bf16x2` types. This PR removes them from instr info, and the non-ftz
legal versions will be emitted instead.

Author: zyx-billy

llvm/lib/Target/NVPTX/NVPTXInstrInfo.td

@@ -334,25 +334,12 @@ multiclass FMINIMUMMAXIMUM<string OpcStr, bit NaN, SDNode OpNode> {
                !strconcat(OpcStr, ".f16x2 \t$dst, $a, $b;"),
                [(set Int32Regs:$dst, (OpNode (v2f16 Int32Regs:$a), (v2f16 Int32Regs:$b)))]>,
                Requires<[useFP16Math, hasSM<80>, hasPTX<70>]>;
-   def bf16rr_ftz :
-     NVPTXInst<(outs Int16Regs:$dst),
-               (ins Int16Regs:$a, Int16Regs:$b),
-               !strconcat(OpcStr, ".ftz.bf16 \t$dst, $a, $b;"),
-               [(set Int16Regs:$dst, (OpNode (bf16 Int16Regs:$a), (bf16 Int16Regs:$b)))]>,
-               Requires<[hasBF16Math, doF32FTZ, hasSM<80>, hasPTX<70>]>;
    def bf16rr :
      NVPTXInst<(outs Int16Regs:$dst),
                (ins Int16Regs:$a, Int16Regs:$b),
                !strconcat(OpcStr, ".bf16 \t$dst, $a, $b;"),
                [(set Int16Regs:$dst, (OpNode (bf16 Int16Regs:$a), (bf16 Int16Regs:$b)))]>,
                Requires<[hasBF16Math, hasSM<80>, hasPTX<70>]>;
-
-   def bf16x2rr_ftz :
-     NVPTXInst<(outs Int32Regs:$dst),
-               (ins Int32Regs:$a, Int32Regs:$b),
-               !strconcat(OpcStr, ".ftz.bf16x2 \t$dst, $a, $b;"),
-               [(set Int32Regs:$dst, (OpNode (v2bf16 Int32Regs:$a), (v2bf16 Int32Regs:$b)))]>,
-               Requires<[hasBF16Math, hasSM<80>, hasPTX<70>, doF32FTZ]>;
    def bf16x2rr :
      NVPTXInst<(outs Int32Regs:$dst),
                (ins Int32Regs:$a, Int32Regs:$b),