can: usb: PEAK-System Technik PCAN-USB specific part

This patch adds the specific part which handles the PCAN-USB adapter from
PEAK-System Technik (http://www.peak-system.com

). The PCAN-USB adapter is
a sja1000 based, mono-channel USB 1.1 adapter compliant with CAN
specifications 2.0A (11-bit ID) and 2.0B (29-bit ID).

Tested-by: Oliver Hartkopp <socketcan@hartkopp.net>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>