thunderbolt: Move control channel messages to tb_msgs.h

We will be forwarding notifications received from the control channel to
the connection manager implementations. This way they can decide what to
do if anything when a notification is received.

To be able to use control channel messages from other files, move them
to tb_msgs.h.

No functional changes intended.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>