ARM: dts: ste: Fix SPI controller node names

SPI controller nodes should be named 'spi' rather than 'ssp'. Fixing the
name enables dtc SPI bus checks.

Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm/boot/dts/ste-u300.dts

@@ -442,7 +442,7 @@
 			dma-names = "rx";
 		};
 
-		spi: ssp@c0006000 {
+		spi: spi@c0006000 {
 			compatible = "arm,pl022", "arm,primecell";
 			reg = <0xc0006000 0x1000>;
 			interrupt-parent = <&vica>;