dmaengine: dmatest: Restore default for channel

BugLink: https://bugs.launchpad.net/bugs/1881178

commit 6b41030 upstream.

In case of dmatest is built-in and no channel was configured test
doesn't run with:

dmatest: Could not start test, no channels configured

Even though description to "channel" parameter claims that default is
any.

Add default channel back as it used to be rather than reject test with
no channel configuration.

Fixes: d53513d ("dmaengine: dmatest: Add support for multi channel testing)
Reported-by: Dijil Mohan <[email protected]>
Signed-off-by: Vladimir Murzin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Vinod Koul <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Kamal Mostafa <[email protected]>
Signed-off-by: Khalid Elmously <[email protected]>

drivers/dma/dmatest.c

@@ -1166,10 +1166,11 @@ static int dmatest_run_set(const char *val, const struct kernel_param *kp)
 		mutex_unlock(&info->lock);
 		return ret;
 	} else if (dmatest_run) {
-		if (is_threaded_test_pending(info))
-			start_threaded_tests(info);
-		else
-			pr_info("Could not start test, no channels configured\n");
+		if (!is_threaded_test_pending(info)) {
+			pr_info("No channels configured, continue with any\n");
+			add_threaded_test(info);
+		}
+		start_threaded_tests(info);
 	} else {
 		stop_threaded_test(info);
 	}