Add linux-firmware into gating

This just adds skeleton code/yaml files to enable gating for
linux-firmware. There is no actual testing done, we just return success
result (with true command). linux-firmware is special, in which we don't
ship any executable, and we don't have any useful test cases. We
expect tests are already done by companies which ship/submit firmware to
the linux-firmware repository upstream.

Resolves: rhbz#1680622

Signed-off-by: Herton R. Krzesinski <herton@redhat.com>

tests/tests.yml

@@ -0,0 +1,9 @@
+- hosts: localhost
+  roles:
+  - role: standard-test-basic
+    tags:
+    - classic
+    tests:
+    - simple:
+        dir: .
+        run: "true"