ksmbd: destroy async_ida in ksmbd_conn_free()

ksmbd: destroy async_ida in ksmbd_conn_free()

When per-connection async_ida was converted from a dynamically
allocated ksmbd_ida to an embedded struct ida, ksmbd_ida_free() was
removed from the connection teardown path but no matching
ida_destroy() was added.  The connection is therefore freed with the
IDA's backing xarray still intact.

The kernel IDA API expects ida_init() and ida_destroy() to be paired
over an object's lifetime, so add the missing cleanup before the
connection is freed.

No leak has been observed in testing; this is a pairing fix to match
the IDA lifetime rules, not a response to a reproduced regression.

Fixes: d40012a83f87 ("cifsd: declare ida statically")
Signed-off-by: DaeMyung Kang <charsyam@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>