ksmbd: separately allocate ci per dentry

xfstests generic/002 test fail when enabling smb2 leases feature.
This test create hard link file, but removeal failed.
ci has a file open count to count file open through the smb client,
but in the case of hard link files, The allocation of ci per inode
cause incorrectly open count for file deletion. This patch allocate
ci per dentry to counts open counts for hard link.

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