Remove incorrect handling of PrimitiveType::F16 in CreateDenseElementsAttrFromLiteral

PrimitiveType::F16 maps to Eigen::half and interpreting it as float will fail. This incorrect handling is removed for now and later on this type along with bf16 and complex types can be supported by constructing appropriate ElementsAttr.
PiperOrigin-RevId: 306574537
Change-Id: Icbd87b24cdc60656ac62de5a7829340f94594a9d

tensorflow/compiler/mlir/xla/hlo_utils.cc

@@ -83,12 +83,11 @@ StatusOr<mlir::DenseElementsAttr> CreateDenseElementsAttrFromLiteral(
                       ConvertTensorShapeToType<mlir::RankedTensorType>(
                           literal.shape(), builder));
 
+  // TODO(hinsu): Support remaining XLA primitive types.
   auto element_type = literal.shape().element_type();
   switch (element_type) {
     case PrimitiveType::PRED:
       return CreateDenseAttrFromLiteral<bool>(type, literal);
-    case PrimitiveType::F16:
-      return CreateDenseAttrFromLiteral<float>(type, literal);
     case PrimitiveType::F32:
       return CreateDenseAttrFromLiteral<float>(type, literal);
     case PrimitiveType::F64: