cifs: handle when server stops supporting multichannel

cifs: handle when server stops supporting multichannel

[ Upstream commit ee1d21794e55ab76505745d24101331552182002 ]

When a server stops supporting multichannel, we will
keep attempting reconnects to the secondary channels today.
Avoid this by freeing extra channels when negotiate
returns no multichannel support.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Stable-dep-of: 78e727e58e54 ("cifs: update iface_last_update on each query-and-update")
Signed-off-by: Sasha Levin <sashal@kernel.org>