Documentation: kunit: fix example run_kunit func to allow spaces in args

Without the quoting, the example will mess up invocations like
$ run_kunit "Something with spaces"

Note: this example isn't valid, but if ever a usecase arises where a
flag argument might have spaces in it, it'll break.
Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Documentation/dev-tools/kunit/running_tips.rst

@@ -15,7 +15,7 @@ It can be handy to create a bash function like:
 .. code-block:: bash
 
 	function run_kunit() {
-	  ( cd "$(git rev-parse --show-toplevel)" && ./tools/testing/kunit/kunit.py run $@ )
+	  ( cd "$(git rev-parse --show-toplevel)" && ./tools/testing/kunit/kunit.py run "$@" )
 	}
 
 .. note::