leds: tlc591xx: fix return value check in tlc591xx_probe()

After device_get_match_data(), tlc591xx is not checked, add
check for it and also check np after dev_of_node.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>