dt-bindings: mfd: Add bindings for SAM9X60 HLCD controller

Add new compatible string for the HLCD controller on SAM9X60 SoC.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Documentation/devicetree/bindings/mfd/atmel-hlcdc.txt

@@ -7,6 +7,7 @@ Required properties:
    "atmel,sama5d2-hlcdc"
    "atmel,sama5d3-hlcdc"
    "atmel,sama5d4-hlcdc"
+   "microchip,sam9x60-hlcdc"
  - reg: base address and size of the HLCDC device registers.
  - clock-names: the name of the 3 clocks requested by the HLCDC device.
    Should contain "periph_clk", "sys_clk" and "slow_clk".