ARM: dts: am57xx: sbc-am57x: remove unneded unit name

This patch fixes the following DTC warnings for am57xx-sbc-am57x.dtb:

"endpoint@0 has a unit name, but no reg property"
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/am57xx-sbc-am57x.dts

@@ -128,7 +128,7 @@ &dss {
 	vdda_video-supply = <&ldoln_reg>;
 
 	port {
-		dpi_lcd_out: endpoint@0 {
+		dpi_lcd_out: endpoint {
 			remote-endpoint = <&lcd_in>;
 			data-lines = <24>;
 		};