mtd: rawnand: mxc: Allow selection of this driver when COMPILE_TEST=y

It just makes NAND maintainers' life easier by allowing them to
compile-test this driver without having ARCH_MXC enabled.

We also need to add a dependency on HAS_IOMEM to make sure the
driver compiles correctly.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

drivers/mtd/nand/raw/Kconfig

@@ -443,7 +443,8 @@ config MTD_NAND_VF610_NFC
 
 config MTD_NAND_MXC
 	tristate "MXC NAND support"
-	depends on ARCH_MXC
+	depends on ARCH_MXC || COMPILE_TEST
+	depends on HAS_IOMEM
 	help
 	  This enables the driver for the NAND flash controller on the
 	  MXC processors.