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/voiceblue.h b/include/configs/voiceblue.h
index 866b72d4..f460610 100644
--- a/include/configs/voiceblue.h
+++ b/include/configs/voiceblue.h
@@ -127,7 +127,7 @@
 #define CONFIG_CMD_BDI
 #define CONFIG_CMD_BOOTD
 #define CONFIG_CMD_DHCP
-#define CONFIG_CMD_ENV
+#define CONFIG_CMD_SAVEENV
 #define CONFIG_CMD_FLASH
 #define CONFIG_CMD_IMI
 #define CONFIG_CMD_JFFS2