i3c master: fix missing destroy_workqueue() on error in i3c_master_register

Add the missing destroy_workqueue() before return from
i3c_master_register in the error handling case.

Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://lore.kernel.org/linux-i3c/20201028091543.136167-1-miaoqinglang@huawei.com