arm64: zynqmp: Use atmel prefix instead of at

This changes was done in mainline and this patch is just following it.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/arch/arm/dts/zynqmp-zc1751-xm015-dc1.dts b/arch/arm/dts/zynqmp-zc1751-xm015-dc1.dts
index 3c20547..7968aa7 100644
--- a/arch/arm/dts/zynqmp-zc1751-xm015-dc1.dts
+++ b/arch/arm/dts/zynqmp-zc1751-xm015-dc1.dts
@@ -92,7 +92,7 @@
 	status = "okay";
 	clock-frequency = <400000>;
 	eeprom@55 {
-		compatible = "at,24c64"; /* 24AA64 */
+		compatible = "atmel,24c64"; /* 24AA64 */
 		reg = <0x55>;
 	};
 };