[3] move aten targets to shared buck file (#79966)

Summary: move aten related targets to the shared buck file

Test Plan: Github CI, sandcastle

Differential Revision: D37323401

Pull Request resolved: https://github.com/pytorch/pytorch/pull/79966
Approved by: https://github.com/iseeyuan

third_party/BUCK.oss

@@ -8,6 +8,20 @@ define_xnnpack()
 
 define_kineto()
 
+# a placeholder for libraries that are not implemented in OSS
+cxx_library(
+    name = "no-op",
+    visibility = ['PUBLIC'],
+)
+
+cxx_library(
+    name = "rt",
+    exported_platform_linker_flags = [
+        ("^linux-.*$", ["-lrt"]),
+    ],
+    visibility = ['PUBLIC'],
+)
+
 cxx_library(
     name = "fmt",
     srcs = ['fmt/src/format.cc'],