[MLIR] [Arith] [NFC] Remove switch statement default label due to warning

[max-kudr]

Summary

We are getting compiler warning because default label is excessive. Removing it for now.

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/vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/lib/Dialect/Arithmetic/IR/ArithmeticOps.cpp:1597:9: warning: default label in switch which covers all enumeration values [-Wcovered-switch-default]

Related to: D117257

[max-kudr]

Please commit it once approved (I do not have commit permission).

[stella.stamenova]

LGTM

mlir/lib/Dialect/Arithmetic/IR/ArithmeticOps.cpp

if (!rhs.isZero()) {
       apf.convertFromAPInt(rhsInt, !isUnsigned, APFloat::rmNearestTiesToEven);
 
       bool equal = apf == rhs;
       if (!equal) {
         // If we had a comparison against a fractional value, we have to adjust
         // the compare predicate and sometimes the value.  rhsInt is rounded
         // towards zero at this point.
         switch (pred) {
-        default:
-          llvm_unreachable("Unexpected integer comparison!");
         case CmpIPredicate::ne: // (float)int != 4.4   --> true
           rewriter.replaceOpWithNewOp<ConstantIntOp>(op, /*value=*/true,
                                                      /*width=*/1);
           return success();
         case CmpIPredicate::eq: // (float)int == 4.4   --> false
           rewriter.replaceOpWithNewOp<ConstantIntOp>(op, /*value=*/false,
                                                      /*width=*/1);
           return success();