can/sja1000: add driver for EMS PCMCIA card

This patch adds the driver for the SJA1000 based PCMCIA card 'CPC-Card' from
EMS Dr. Thomas Wuensche (http://www.ems-wuensche.de

).

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Acked-by: Markus Plessing <plessing@ems-wuensche.com>
Signed-off-by: David S. Miller <davem@davemloft.net>