USB: serial: Add support for ViVOtech ViVOpay devices.

Add support for USB serial interface provided by ViVOtech ViVOpay devices via
new driver vivopay-serial.  Currently only the ViVOpay 8800 device is supported,
but support for similar devices can be added by adding the appropriate device
IDs to the driver.

Signed-off-by: Forest Bond <forest.bond@outpostembedded.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>