dts: mtd: refactor JESD216 support

jedec,jesd216.yaml has properties for any memory device that conforms
to the JESD216 specification.  This file at a minimum should be
included in the binding for any driver that interacts with such a
device.

jedec,spi-nor-common.yaml extends jedec,jesd216 with additional
parameters useful for memory devices that are not available from
standard JESD216 parameter tables.  This file may be included instead
of jedec,jesd216.yaml if a driver is able to support additional
functionality related to the extended description.

jedec,spi-nor.yaml remains the binding for the Zephyr SPI_NOR driver
alone.

Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>