rename CONFIG_CMD_ENV to CONFIG_CMD_SAVEENV

The CONFIG_CMD_ENV option controls enablement of the `saveenv` command
rather than a generic "env" command, or anything else related to the
environment.  So, let's make sure the define is named accordingly.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/include/configs/MPC8313ERDB.h b/include/configs/MPC8313ERDB.h
index 58a26e1..0ef4eba 100644
--- a/include/configs/MPC8313ERDB.h
+++ b/include/configs/MPC8313ERDB.h
@@ -430,7 +430,7 @@
 #define CONFIG_CMD_PCI
 
 #if defined(CONFIG_SYS_RAMBOOT) && !defined(CONFIG_NAND_U_BOOT)
-    #undef CONFIG_CMD_ENV
+    #undef CONFIG_CMD_SAVEENV
     #undef CONFIG_CMD_LOADS
 #endif