Redundant environment: move flag definitions to header file

Instead of defining the flags sevaral times in different source files
(which is error prone), move them to a central place in a header file.

Signed-off-by: Wolfgang Denk <wd@denx.de>
diff --git a/include/environment.h b/include/environment.h
index b9924fd..203f731 100644
--- a/include/environment.h
+++ b/include/environment.h
@@ -122,6 +122,9 @@
 
 #ifdef CONFIG_SYS_REDUNDAND_ENVIRONMENT
 # define ENV_HEADER_SIZE	(sizeof(uint32_t) + 1)
+
+# define ACTIVE_FLAG   1
+# define OBSOLETE_FLAG 0
 #else
 # define ENV_HEADER_SIZE	(sizeof(uint32_t))
 #endif