ARM: dts: imx6sl: Add spi aliases

Add spi aliases.

While at it, keep the aliases entries sorted.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/boot/dts/imx6sl.dtsi

@@ -13,16 +13,20 @@
 
 / {
 	aliases {
-		serial0 = &uart1;
-		serial1 = &uart2;
-		serial2 = &uart3;
-		serial3 = &uart4;
-		serial4 = &uart5;
 		gpio0 = &gpio1;
 		gpio1 = &gpio2;
 		gpio2 = &gpio3;
 		gpio3 = &gpio4;
 		gpio4 = &gpio5;
+		serial0 = &uart1;
+		serial1 = &uart2;
+		serial2 = &uart3;
+		serial3 = &uart4;
+		serial4 = &uart5;
+		spi0 = &ecspi1;
+		spi1 = &ecspi2;
+		spi2 = &ecspi3;
+		spi3 = &ecspi4;
 	};
 
 	cpus {