x86: Correct spi node alias

With recent changes spi node was moved to a place as a subnode under
pch, so update the alias to refer to its correct place as well.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/dts/broadwell_som-6896.dts b/arch/x86/dts/broadwell_som-6896.dts
index 4e9e410..7b2c515 100644
--- a/arch/x86/dts/broadwell_som-6896.dts
+++ b/arch/x86/dts/broadwell_som-6896.dts
@@ -10,7 +10,7 @@
 	compatible = "advantech,som-6896", "intel,broadwell";
 
 	aliases {
-		spi0 = "/spi";
+		spi0 = &spi;
 	};
 
 	config {
@@ -34,7 +34,7 @@
 			reg = <0x0000f800 0 0 0 0>;
 			compatible = "intel,pch9";
 
-			spi {
+			spi: spi {
 				#address-cells = <1>;
 				#size-cells = <0>;
 				compatible = "intel,ich-spi";