[bazel] fix build for 4790578

Author: metaflow

utils/bazel/llvm-project-overlay/mlir/unittests/BUILD.bazel

@@ -22,6 +22,7 @@ cc_test(
         "//llvm:Support",
         "//llvm:TestingSupport",
         "//mlir:Debug",
+        "//mlir:FunctionInterfaces",
         "//mlir:IR",
         "//mlir:Support",
         "//third-party/unittest:gmock",