mtd: rawnand: Get rid of nand_flash_dev forward declation

nand_scan[with_ids]() have been moved at the end of the file. We can
now get rid of of the nand_flash_dev forward declaration.
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

include/linux/mtd/rawnand.h

@@ -25,7 +25,6 @@
 #include <linux/types.h>
 
 struct nand_chip;
-struct nand_flash_dev;
 
 /* The maximum number of NAND chips in an array */
 #define NAND_MAX_CHIPS		8