cifs: fix stray unlock in cifs_chan_skip_or_disable

A recent change moved the code that decides to skip
a channel or disable multichannel entirely, into a
helper function.

During this, a mutex_unlock of the session_mutex
should have been removed. Doing that here.

Fixes: f591062b ("cifs: handle servers that still advertise multichannel after disabling")
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/smb/client/smb2pdu.c

@@ -195,7 +195,6 @@ cifs_chan_skip_or_disable(struct cifs_ses *ses,
 		pserver = server->primary_server;
 		cifs_signal_cifsd_for_reconnect(pserver, false);
 skip_terminate:
-		mutex_unlock(&ses->session_mutex);
 		return -EHOSTDOWN;
 	}