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>

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>;
 	};
 };

arch/arm/dts/zynqmp-zcu102-revA.dts

@@ -422,7 +422,7 @@
 			 * 768B - 1024B address 0x57
 			 */
 			eeprom: eeprom@54 { /* u23 */
-				compatible = "at,24c08";
+				compatible = "atmel,24c08";
 				reg = <0x54>;
 			};
 		};