i2c: i2c-diolan-u2c: different usb endpoints for DLN-2-U2C

The previous diolan adapter uses other out/in endpoints than
the current DLN-2-U2C in compatibility mode.
They changed from 0x2/0x84 to 0x3/0x83.
This patch gets the endpoints from the usb interface, instead
of hardcode them in the driver.

This was tested on a current DLN-2-U2C board.

Signed-off-by: Martin Vogt <mvogt1@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>