ARM: dts: keystone2: add SPI aliases for davinci SPI nodes

Add aliases for SPI nodes in order for it to be probed by the DM
framework.

Signed-off-by: Vignesh R <vigneshr@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Jagan Teki <jteki@openedev.com>
diff --git a/arch/arm/dts/keystone.dtsi b/arch/arm/dts/keystone.dtsi
index f39b969..be97f3f 100644
--- a/arch/arm/dts/keystone.dtsi
+++ b/arch/arm/dts/keystone.dtsi
@@ -19,6 +19,9 @@
 
 	aliases {
 		serial0	= &uart0;
+		spi0 = &spi0;
+		spi1 = &spi1;
+		spi2 = &spi2;
 	};
 
 	chosen {