mtd: rawnand: au1550nd: Remove unneeded gpio.h inclusion

We don't use the GPIO API in this driver, let's just remove the
<linux/gpio.h> inclusion.
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

drivers/mtd/nand/raw/au1550nd.c

@@ -8,7 +8,6 @@
  */
 
 #include <linux/slab.h>
-#include <linux/gpio.h>
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/mtd/mtd.h>