cifs: Move the SMB1 transport code out of transport.c

Shrink the size of cifs.ko when SMB1 is not enabled in the config
by moving the SMB1 transport code to different file.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cifs@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>