dt-bindings: mtd: nand-controller: Fix a comment in the examples

dt-bindings: mtd: nand-controller: Fix a comment in the examples

The controller properties should be in the controller 'parent' node,
while properties in the children nodes are specific to the NAND
*chip*. This error was already present during the yaml conversion.

Fixes: 2d472aba15ff ("mtd: nand: document the NAND controller/NAND chip DT representation")
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/linux-mtd/20211216111654.238086-3-miquel.raynal@bootlin.com