* MTD SPI driver for Microchip 23K256 (and similar) serial SRAM

Required properties:
- #address-cells, #size-cells : Must be present if the device has sub-nodes
  representing partitions.
- compatible : Must be one of "microchip,mchp23k256" or "microchip,mchp23lcv1024"
- reg : Chip-Select number
- spi-max-frequency : Maximum frequency of the SPI bus the chip can operate at

Example:

	spi-sram@0 {
		#address-cells = <1>;
		#size-cells = <1>;
		compatible = "microchip,mchp23k256";
		reg = <0>;
		spi-max-frequency = <20000000>;
	};