ksmbd: don't align last entry offset in smb2 query directory

When checking smb2 query directory packets from other servers,
OutputBufferLength is different with ksmbd. Other servers add an unaligned
next offset to OutputBufferLength for the last entry.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>