mtd: rawnand: mxc: Avoid inclusion of asm/mach headers

asm/mach/flash.h does not seem to be needed, drop this #include to make
the code completely machine and arch independent and allow one to
compile it when COMPILE_TEST=y.
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

drivers/mtd/nand/raw/mxc_nand.c

@@ -34,8 +34,6 @@
 #include <linux/completion.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
-
-#include <asm/mach/flash.h>
 #include <linux/platform_data/mtd-mxc_nand.h>
 
 #define DRIVER_NAME "mxc_nand"