This patch limits the PEAK PCAN-PC Card driver to systems with ioports. Fixes a
compile time breakage on SH:

    drivers/net/can/sja1000/peak_pcmcia.c:626:2: error:
        implicit declaration of function 'ioport_unmap'
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>