Squashed 'dts/upstream/' content from commit aaba2d45dc2a

git-subtree-dir: dts/upstream
git-subtree-split: aaba2d45dc2a1b3bbb710f2a3808ee1c9f340abe
diff --git a/src/arm64/apple/multi-die-cpp.h b/src/arm64/apple/multi-die-cpp.h
new file mode 100644
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--- /dev/null
+++ b/src/arm64/apple/multi-die-cpp.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0+ OR MIT
+ *
+ * C preprocessor macros for t600x multi die support.
+ */
+
+#ifndef __DTS_APPLE_MULTI_DIE_CPP_H
+#define __DTS_APPLE_MULTI_DIE_CPP_H
+
+#ifndef __stringify
+#define __stringify_1(x...)     #x
+#define __stringify(x...)       __stringify_1(x)
+#endif
+
+#ifndef __concat
+#define __concat_1(x, y...)     x ## y
+#define __concat(x, y...)       __concat_1(x, y)
+#endif
+
+#define DIE_NODE(a) __concat(a, DIE)
+#define DIE_LABEL(a) __stringify(__concat(a, DIE))
+
+#endif /* !__DTS_APPLE_MULTI_DIE_CPP_H */