mtd: rawnand: arasan: Fix a macro parameter

This macro is not yet being used so the compilers never complained
about it.

Fix the macro before using it.
Signed-off-by: NMiquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210505213750.257417-21-miquel.raynal@bootlin.com

drivers/mtd/nand/raw/arasan-nand-controller.c

@@ -91,7 +91,7 @@
 
 #define DATA_INTERFACE_REG		0x6C
 #define   DIFACE_SDR_MODE(x)		FIELD_PREP(GENMASK(2, 0), (x))
-#define   DIFACE_DDR_MODE(x)		FIELD_PREP(GENMASK(5, 3), (X))
+#define   DIFACE_DDR_MODE(x)		FIELD_PREP(GENMASK(5, 3), (x))
 #define   DIFACE_SDR			0
 #define   DIFACE_NVDDR			BIT(9)