ksmbd: move credit charge deduction under processing request

mainline inclusion
from mainline-5.17-rc1
commit 914d7e57
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I60T7G
CVE: NA

Reference: https://git.kernel.org/torvalds/linux/c/914d7e5709ac



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Moves the credit charge deduction from total_credits under the processing
a request. When repeating smb2 lock request and other command request,
there will be a problem that ->total_credits does not decrease.

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>