dt-bindings: nvmem: Fix example

dt-bindings: nvmem: Fix example

Despite not being listed nor required within the top level nvmem yaml
file, the "compatible" property is mandatory and is actually enforced by
all the nvmem provider bindings.

Unfortunately, the lack of compatible in the nvmem.yaml to level
description file lead to the example not matching anything and thus not
being checked at all.

Let's pick a compatible almost randomly (one which is already used with
the qfprom label) to make the example at least valid on a semantic
point of view and getting it checked.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20221118063932.6418-7-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>