ksmbd: replace usage of found with dedicated list iterator variable

mainline inclusion
from mainline-v5.18-rc1
commit edf5f054
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I6KEWO?from=project-issue
CVE: CVE-2023-1193

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=edf5f0548fbb77e20b898460dc25281b0f4d974d

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

To move the list iterator variable into the list_for_each_entry_*()
macro in the future it should be avoided to use the list iterator
variable after the loop body.

To *never* use the list iterator variable after the loop it was
concluded to use a separate iterator variable instead of a
found boolean [1].

This removes the need to use a found variable and simply checking if
the variable was set, can determine if the break/goto was hit.

Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/


Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Reviewed-by: Hyunchul Lee <hyc.lee@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Zizhi Wo <wozizhi@huawei.com>