Blackfin: tweak embedded LDR env config option

Use the common config option for extracting the environment for embedding
into LDR files and clarify the LDR-specific option.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/include/configs/bf518f-ezbrd.h b/include/configs/bf518f-ezbrd.h
index 3db8171..4928403 100644
--- a/include/configs/bf518f-ezbrd.h
+++ b/include/configs/bf518f-ezbrd.h
@@ -109,7 +109,7 @@
 #define CONFIG_ENV_SIZE		0x2000
 #define CONFIG_ENV_SECT_SIZE	0x2000
 #endif
-#define ENV_IS_EMBEDDED_CUSTOM
+#define CONFIG_ENV_IS_EMBEDDED_IN_LDR
 
 
 /*