dts/arm: Add armv8m

Change-Id: I49a4e69363b184120da864e0be9fb8febc3849d2
Reviewed-on: https://pigweed-review.googlesource.com/c/zephyr/zephyr-bazel/+/295870
Reviewed-by: Kevin Zeng <zengk@google.com>
Commit-Queue: Yicheng Li <yichengli@google.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
diff --git a/dts/arm/BUILD.bazel b/dts/arm/BUILD.bazel
index b939790..ed0e9f0 100644
--- a/dts/arm/BUILD.bazel
+++ b/dts/arm/BUILD.bazel
@@ -20,3 +20,10 @@
         "armv7-m.dtsi",
     ],
 )
+
+filegroup(
+    name = "armv8-m",
+    srcs = [
+        "armv8-m.dtsi",
+    ],
+)