Add //tools:armhf-debian to the default environment group

Everything builds for the Jetson anyways, so let's just stick to it.
More compilers aren't a bad thing.  This will prevent more of the code
base from needing to be annotated.

Change-Id: I501b384c8073e245f11f0e0c3e5f9b494ad89a66
diff --git a/third_party/eigen/BUILD b/third_party/eigen/BUILD
index 8fe7fa6..e66382c 100644
--- a/third_party/eigen/BUILD
+++ b/third_party/eigen/BUILD
@@ -20,9 +20,7 @@
     ) + ["unsupported/Eigen/MatrixFunctions"] + glob([
         "unsupported/Eigen/src/MatrixFunctions/*.h",
     ]),
-    compatible_with = mcu_cpus + [
-        "//tools:armhf-debian",
-    ],
+    compatible_with = mcu_cpus,
     includes = ["."],
     visibility = ["//visibility:public"],
 )