thermal/drivers/mediatek/lvts: Fix parameter check in lvts_debugfs_init()

The documentation says "If an error occurs, ERR_PTR(-ERROR) will be
returned" but the current code checks against a NULL pointer returned.

Fix this by checking if IS_ERR().

Signed-off-by: Minjie Du <duminjie@vivo.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230713042413.2519-1-duminjie@vivo.com

Author: Minjie Du

drivers/thermal/mediatek/lvts_thermal.c

@@ -201,7 +201,7 @@ static int lvts_debugfs_init(struct device *dev, struct lvts_domain *lvts_td)
 	int i;
 
 	lvts_td->dom_dentry = debugfs_create_dir(dev_name(dev), NULL);
-	if (!lvts_td->dom_dentry)
+	if (IS_ERR(lvts_td->dom_dentry))
 		return 0;
 
 	for (i = 0; i < lvts_td->num_lvts_ctrl; i++) {