ksmbd: fix an oops in error handling in smb2_open()

mainline inclusion
from mainline-5.15-rc1
commit 8b99f350
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I60T7G
CVE: NA

Reference: https://git.kernel.org/torvalds/linux/c/8b99f3504b68



-------------------------------

If smb2_get_name() then name is an error pointer.  In the clean up
code, we try to kfree() it and that will lead to an Oops.  Set it to
NULL instead.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Zhong Jinghua <zhongjinghua@huawei.com>