ARM: dts: Add aliases for i.MX27 SPI controller

Add aliases to determine the proper SPI bus number.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/boot/dts/imx27.dtsi

@@ -25,6 +25,9 @@ aliases {
 		gpio3 = &gpio4;
 		gpio4 = &gpio5;
 		gpio5 = &gpio6;
+		spi0 = &cspi1;
+		spi1 = &cspi2;
+		spi2 = &cspi3;
 	};
 
 	avic: avic-interrupt-controller@e0000000 {