ksmbd: fix read on the uninitialized send_ctx

mainline inclusion
from mainline-5.15-rc1
commit b8fc94cd
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I60T7G
CVE: NA

Reference: https://git.kernel.org/torvalds/linux/c/b8fc94cdb144



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If st->status is not SMB_DIRECT_CS_CONNECTED, It will jump done label
and accessing the uninitialized send_ctxi by smb_direct_flush_send_list
will cause kernel oops. This patch just return -ENOTCONN to avoid it.

Reported-by: Coverity Scan <scan-admin@coverity.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>