can: let SJA1000 driver depend on HAS_IOMEM

Fixes this compile error on s390:

drivers/net/can/sja1000/sja1000_platform.c: In function 'sp_read_reg':
drivers/net/can/sja1000/sja1000_platform.c:42: error: implicit declaration of function 'ioread8'
drivers/net/can/sja1000/sja1000_platform.c: In function 'sp_write_reg':
drivers/net/can/sja1000/sja1000_platform.c:47: error: implicit declaration of function 'iowrite8'
drivers/net/can/sja1000/sja1000_platform.c: In function 'sp_probe':
drivers/net/can/sja1000/sja1000_platform.c:79: error: implicit declaration of function 'ioremap_nocache'

Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/can/Kconfig

@@ -36,7 +36,7 @@ config CAN_CALC_BITTIMING
 	  If unsure, say Y.
 
 config CAN_SJA1000
-	depends on CAN_DEV
+	depends on CAN_DEV && HAS_IOMEM
 	tristate "Philips SJA1000"
 	---help---
 	  Driver for the SJA1000 CAN controllers from Philips or NXP