dt-bindings: mtd: partitions: Move "sercomm,scpart-id" to partition.yaml

dt-bindings: mtd: partitions: Move "sercomm,scpart-id" to partition.yaml

Defining child node properties specific to the parent schema doesn't work
unless all the child node properties are known. They aren't known because
any partition can define its own properties. The solution to this is
typically something like spi-peripheral-props.yaml, but that's overkill for
this single property. Just move it to partition.yaml instead.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>