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/common/env_flash.c b/common/env_flash.c
index 75ee8dd..00792cd 100644
--- a/common/env_flash.c
+++ b/common/env_flash.c
@@ -34,10 +34,10 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-#if defined(CONFIG_CMD_ENV) && defined(CONFIG_CMD_FLASH)
+#if defined(CONFIG_CMD_SAVEENV) && defined(CONFIG_CMD_FLASH)
 #define CMD_SAVEENV
 #elif defined(CONFIG_ENV_ADDR_REDUND)
-#error Cannot use CONFIG_ENV_ADDR_REDUND without CONFIG_CMD_ENV & CONFIG_CMD_FLASH
+#error Cannot use CONFIG_ENV_ADDR_REDUND without CONFIG_CMD_SAVEENV & CONFIG_CMD_FLASH
 #endif
 
 #if defined(CONFIG_ENV_SIZE_REDUND) && (CONFIG_ENV_SIZE_REDUND < CONFIG_ENV_SIZE)