migration/multifd: Drop unnecessary helper to destroy IOC

Both socket_send_channel_destroy() and multifd_send_channel_destroy() are
unnecessary wrappers to destroy an IOC, as the only thing to do is to
release the final IOC reference.  We have plenty of code that destroys an
IOC using direct unref() already; keep that style.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240222095301.171137-6-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
3 files changed