pxa: balloon3/colibri_pxa270: fix environment optionally being nowhere

I couldn't quite figure out whether or not CONFIG_SYS_ENV_IS_NOWHERE
actually ever worked but nowadays this is called CONFIG_ENV_IS_NOWHERE.

Signed-off-by: Marcel Ziswiler <marcel@ziswiler.com>
diff --git a/include/configs/vpac270.h b/include/configs/vpac270.h
index e54601d..887433b 100644
--- a/include/configs/vpac270.h
+++ b/include/configs/vpac270.h
@@ -221,7 +221,7 @@
 
 #else	/* No flash */
 #define	CONFIG_SYS_NO_FLASH
-#define	CONFIG_SYS_ENV_IS_NOWHERE
+#define	CONFIG_ENV_IS_NOWHERE
 #endif
 
 /*