ARM: at91/sama5d34ek.dts: remove not needed compatibility string

"atmel,sama5ek" compatibility sting does not correspond to a
useful board configuration. This d34ek.dts is the only sama5d3
.dts file affected.

Reported-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

arch/arm/boot/dts/sama5d34ek.dts

@@ -12,7 +12,7 @@
 
 / {
 	model = "Atmel SAMA5D34-EK";
-	compatible = "atmel,sama5d34ek", "atmel,sama5ek", "atmel,sama5d3xmb", "atmel,sama5d3xcm", "atmel,sama5d3", "atmel,sama5";
+	compatible = "atmel,sama5d34ek", "atmel,sama5d3xmb", "atmel,sama5d3xcm", "atmel,sama5d3", "atmel,sama5";
 
 	ahb {
 		apb {