can: grcan: add missing Kconfig dependency to HAS_IOMEM

On ARCHs without IOMEM support the grcan driver fails to link due to
missing iomem functionality. This patch adds the missing Kconfig
dependency to HAS_IOMEM.

Link: https://lore.kernel.org/r/20210309140424.3331010-1-mkl@pengutronix.deReported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/Kconfig

@@ -103,7 +103,7 @@ config CAN_FLEXCAN
 
 config CAN_GRCAN
 	tristate "Aeroflex Gaisler GRCAN and GRHCAN CAN devices"
-	depends on OF && HAS_DMA
+	depends on OF && HAS_DMA && HAS_IOMEM
 	help
 	  Say Y here if you want to use Aeroflex Gaisler GRCAN or GRHCAN.
 	  Note that the driver supports little endian, even though little