[llvm] [RISCV] Don't cost Fmv for Zfinx in isFPImmLegal. (PR #107361)

[Luke Lau via llvm-commits]

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@@ -2288,10 +2288,11 @@ bool RISCVTargetLowering::isFPImmLegal(const APFloat &Imm, EVT VT,
     return true;
 
   // Building an integer and then converting requires a fmv at the end of
-  // the integer sequence.
+  // the integer sequence. The fmv is not requires for Zfinx.
----------------
lukel97 wrote:

```suggestion
  // the integer sequence. The fmv is not required for Zfinx.
```

https://github.com/llvm/llvm-project/pull/107361