Create a custom open method for SHEARWATER family.
This method can be used to pass a reference to a dc_serial_t
structure. In this way the applications can implement their
own implementation for a serial communication and set their
callbacks for the basic serial functions.
Signed-off-by: Claudiu Olteanu <olteanu.claudiu@ymail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>