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/MPC8610HPCD.h b/include/configs/MPC8610HPCD.h
index 7a9e57f..1091043 100644
--- a/include/configs/MPC8610HPCD.h
+++ b/include/configs/MPC8610HPCD.h
@@ -489,7 +489,7 @@
 #define CONFIG_CMD_MII
 
 #if defined(CONFIG_SYS_RAMBOOT)
-#undef CONFIG_CMD_ENV
+#undef CONFIG_CMD_SAVEENV
 #endif
 
 #if defined(CONFIG_PCI)