doc: dev-tools: kselftest.rst: update contributing new tests

Add a description that kernel config options should be added into a
config file that is placed next to the newly added test.

Signed-off-by: Anders Roxell <[email protected]>
Reviewed-by: Shuah Khan (Samsung OSG) <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
diff --git a/Documentation/dev-tools/kselftest.rst b/Documentation/dev-tools/kselftest.rst
index 3bf371a..6f653ac 100644
--- a/Documentation/dev-tools/kselftest.rst
+++ b/Documentation/dev-tools/kselftest.rst
@@ -156,6 +156,11 @@
    installed by the distro on the system should be the primary focus to be able
    to find regressions.
 
+ * If a test needs specific kernel config options enabled, add a config file in
+   the test directory to enable them.
+
+   e.g: tools/testing/selftests/android/ion/config
+
 Test Harness
 ============