rename CFG_ENV_IS_IN_FLASH in CONFIG_ENV_IS_IN_FLASH

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
diff --git a/board/RPXlite_dw/README b/board/RPXlite_dw/README
index 60580c9..14296b2 100644
--- a/board/RPXlite_dw/README
+++ b/board/RPXlite_dw/README
@@ -21,7 +21,7 @@
 make RPXlite_DW_64_config
 make all
 
-2. CFG_ENV_IS_IN_FLASH/CONFIG_ENV_IS_IN_NVRAM
+2. CONFIG_ENV_IS_IN_FLASH/CONFIG_ENV_IS_IN_NVRAM
 
 The default environment parameter is stored in FLASH because it is a common choice for
 environment parameter.So I make NVRAM as backup parameter storeage.The reason why I