i3c: master: Fix error return in cdns_i3c_master_probe()

Fix to return negative error code -ENOMEM from the error handling
case instead of 0.

Fixes: 603f2bee

 ("i3c: master: Add driver for Cadence IP")
Signed-off-by: Jing Xiangfeng <jingxiangfeng@huawei.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://lore.kernel.org/linux-i3c/20200911033350.23904-1-jingxiangfeng@huawei.com