mtd: nand: sunxi: fix generic nand binding reference

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

Documentation/devicetree/bindings/mtd/sunxi-nand.txt

@@ -21,7 +21,7 @@ Optional properties:
 - nand-ecc-mode : one of the supported ECC modes ("hw", "hw_syndrome", "soft",
   "soft_bch" or "none")
 
-see Documentation/devicetree/mtd/nand.txt for generic bindings.
+see Documentation/devicetree/bindings/mtd/nand.txt for generic bindings.
 
 
 Examples: