drivers: soc: ti: knav_qmss_queue: Fix error return code in knav_queue_probe

Fix to return the error code from of_get_child_by_name() instaed of 0
in knav_queue_probe().

Fixes: 41f93af9 ("soc: ti: add Keystone Navigator QMSS driver")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>