Fix ROCM build by removing optional keyword from protobuf definition

PiperOrigin-RevId: 321025792
Change-Id: I676c7672b9de7187bac9763cf8d742321bf8804f
diff --git a/tensorflow/core/tpu/kernels/tpu_compile.proto b/tensorflow/core/tpu/kernels/tpu_compile.proto
index 03c0a40..bdf7544 100644
--- a/tensorflow/core/tpu/kernels/tpu_compile.proto
+++ b/tensorflow/core/tpu/kernels/tpu_compile.proto
@@ -171,15 +171,15 @@
   repeated TensorProto guaranteed_constants = 7;
 
   // MLIR module definition.
-  optional string mlir_module = 8;
+  string mlir_module = 8;
 
   // A set of named functions used as the input to lowering to Hlo when mlir is
   // not used.
-  optional FunctionDefLibrary fdef_lib = 9;
+  FunctionDefLibrary fdef_lib = 9;
 
   // The version of the graph definition used to lower TF function to Hlo.
-  optional int32 graph_def_version = 10;
+  int32 graph_def_version = 10;
 
   // Function containing the computation to compile.
-  optional NameAttrList function = 11;
+  NameAttrList function = 11;
 }