mx25pdk: Remove duplicated define

The CONFIG_SYS_MMC_ENV_DEV is duplicated, drop it.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
diff --git a/include/configs/mx25pdk.h b/include/configs/mx25pdk.h
index 57e2a6d..bb100c4 100644
--- a/include/configs/mx25pdk.h
+++ b/include/configs/mx25pdk.h
@@ -58,8 +58,6 @@
 #define CONFIG_ENV_SIZE        (8 * 1024)
 #define CONFIG_SYS_MMC_ENV_DEV		0
 
-#define CONFIG_SYS_MMC_ENV_DEV 0
-
 /* U-Boot general configuration */
 #define CONFIG_AUTO_COMPLETE
 #define CONFIG_SYS_CBSIZE	1024	/* Console I/O Buffer Size  */