usb: typec: tcpm: remove tcpm dir if no children

If config tcpm as module, module unload will not remove tcpm dir,
then the next module load will have problem: the rootdir is NULL
but tcpm dir is still there, so tcpm_debugfs_init() will create
tcpm dir again with failure, fix it by remove the tcpm dir if no
children.

Cc: [email protected] # v4.15+
Fixes: 4b4e02c ("typec: tcpm: Move out of staging")
Signed-off-by: Li Jun <[email protected]>
Reviewed-by: Guenter Roeck <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Junlisuzhou

drivers/usb/typec/tcpm/tcpm.c

@@ -597,6 +597,10 @@ static void tcpm_debugfs_exit(struct tcpm_port *port)
 	mutex_unlock(&port->logbuffer_lock);
 
 	debugfs_remove(port->dentry);
+	if (list_empty(&rootdir->d_subdirs)) {
+		debugfs_remove(rootdir);
+		rootdir = NULL;
+	}
 }
 
 #else