dt-bindings: spi: atmel-quadspi: update example to new clock binding

Introduced in:
commit b6055787 ("ARM: dts: at91: sama5d2: switch to new clock binding")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Boris Brezillon <bbrezillon@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/spi/atmel-quadspi.txt

@@ -19,7 +19,7 @@ spi@f0020000 {
 	reg = <0xf0020000 0x100>, <0xd0000000 0x8000000>;
 	reg-names = "qspi_base", "qspi_mmap";
 	interrupts = <52 IRQ_TYPE_LEVEL_HIGH 7>;
-	clocks = <&spi0_clk>;
+	clocks = <&pmc PMC_TYPE_PERIPHERAL 52>;
 	#address-cells = <1>;
 	#size-cells = <0>;
 	pinctrl-names = "default";