Remove a can't-happen match failure

Author: krzysz00

mlir/lib/Dialect/Arith/Transforms/ExpandOps.cpp

@@ -657,11 +657,7 @@ struct ScalingExtFOpConverter : public OpRewritePattern<arith::ScalingExtFOp> {
       scaleOperand = b.create<arith::TruncFOp>(scaleTy, scaleOperand, nullptr,
                                                op.getFastmathAttr());
     }
-    if (!llvm::isa<Float8E8M0FNUType>(scaleETy)) {
-      return rewriter.notifyMatchFailure(
-          op, "scaling_extf is using scales of type which can not be converted "
-              "to f8E8M0FNU");
-    }
+
     Type resultTy = op.getType();
     // extf on scale will essentially create floating point number
     // of type resulTy that is 2^scale and will also propagate NaNs