greybus: loopback_test: Cancel only the tests running on selected devices

When starting a loopback test, it cancels all currently running tests on
all loopback devices. When -m argument is given, which runs the test on
specific loopback devices, only the tests running on the selected
devices need to be cancelled before starting new tests.
Signed-off-by: Ryan Lim <limryan@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/tools/loopback_test.c

@@ -780,7 +780,8 @@ static void prepare_devices(struct loopback_test *t)
 
 	/* Cancel any running tests */
 	for (i = 0; i < t->device_count; i++)
-		write_sysfs_val(t->devices[i].sysfs_entry, "type", 0);
+		if (device_enabled(t, i))
+			write_sysfs_val(t->devices[i].sysfs_entry, "type", 0);
 
 
 	for (i = 0; i < t->device_count; i++) {