common: fb_nand: won't compile

Somehow this got overlooked when getting rid of nand_info.

Small patch, won't affect anything else, no reason to wait for the
next cycle.

Signed-off-by: Sergey Kubushyn <ksi@koi8.net>

common/fb_nand.c

@@ -34,7 +34,7 @@ __weak int board_fastboot_write_partition_setup(char *name)
 }
 
 static int fb_nand_lookup(const char *partname, char *response,
-			  struct mtd_info **nand,
+			  struct mtd_info **mtd,
 			  struct part_info **part)
 {
 	struct mtd_device *dev;