avr32: fixup definitions to ATMEL_BASE_xxx

Signed-off-by: Andreas Bießmann <biessmann@corscience.de>
diff --git a/include/configs/hammerhead.h b/include/configs/hammerhead.h
index 8ca04ea..1f20fff 100644
--- a/include/configs/hammerhead.h
+++ b/include/configs/hammerhead.h
@@ -59,7 +59,8 @@
  */
 #define CONFIG_SYS_PLL0_OPT			0x04
 
-#define CONFIG_USART1			1
+#define CONFIG_USART_BASE			ATMEL_BASE_USART1
+#define CONFIG_USART_ID				1
 
 #define CONFIG_HOSTNAME			hammerhead