dt-bindings: mtd: nand-controller: Fix the reg property description

The reg property of a NAND device always references the chip-selects.
The ready/busy lines are described in the nand-rb property. I believe
this was a harmless copy/paste error during the conversion to yaml.

Fixes: 212e4969 ("dt-bindings: mtd: Add YAML schemas for the generic NAND options")
Signed-off-by: NMiquel Raynal <miquel.raynal@bootlin.com>
Acked-by: NRob Herring <robh@kernel.org>
Link: https://lore.kernel.org/linux-mtd/20211216111654.238086-2-miquel.raynal@bootlin.com

Documentation/devicetree/bindings/mtd/nand-controller.yaml

@@ -55,7 +55,7 @@ patternProperties:
     properties:
       reg:
         description:
-          Contains the native Ready/Busy IDs.
+          Contains the chip-select IDs.
 
       nand-ecc-engine:
         allOf: