ksmbd: add support for smb2 max credit parameter

mainline inclusion
from mainline-5.17-rc1
commit 004443b3
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I60T7G
CVE: NA

Reference: https://git.kernel.org/torvalds/linux/c/004443b3f6d7



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Add smb2 max credits parameter to adjust maximum credits value to limit
number of outstanding requests.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Zhong Jinghua <zhongjinghua@huawei.com>