Fix hello_world target visibility

Fix the target visibility to support bazel query properly

Change-Id: I212ba7c9b8a59eae5310a436902f2e237236df26

sw/device/examples/hello_world/BUILD

diff --git a/sw/device/examples/hello_world/BUILD b/sw/device/examples/hello_world/BUILD
index ea9de45..b9b2189 100644
--- a/sw/device/examples/hello_world/BUILD
+++ b/sw/device/examples/hello_world/BUILD
@@ -63,6 +63,7 @@
     tags = [
         "verilator",
     ],
+    visibility = ["//sw/device/tests:sw_device_test_group"],
 )
 
 sh_test(

sw/device/tests/BUILD

diff --git a/sw/device/tests/BUILD b/sw/device/tests/BUILD
index 64f3b94..85e2b9c 100644
--- a/sw/device/tests/BUILD
+++ b/sw/device/tests/BUILD
@@ -3,11 +3,16 @@
 # Licensed under the Apache License, Version 2.0, see LICENSE for details.
 # SPDX-License-Identifier: Apache-2.0
 
-load("//rules:matcha_test.bzl", "matcha_dv_test", "matcha_verilator_test")
 load("//rules:matcha.bzl", "NEXUS_CORE_TARGETS", "OPENTITAN_CPU", "sec_flash_binary")
+load("//rules:matcha_test.bzl", "matcha_dv_test", "matcha_verilator_test")
 
 package(default_visibility = ["//visibility:public"])
 
+package_group(
+    name = "sw_device_test_group",
+    packages = ["//sw/device/tests/..."],
+)
+
 sec_fpga_device = {
     "fpga_nexus": [NEXUS_CORE_TARGETS.get("secure_core")],
 }