env: Discern environment coming from external storage

Add another custom environment flag which discerns environment coming
from external storage from environment set by U-Boot itself.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Tom Rini <trini@konsulko.com>

env/flash.c

@@ -351,7 +351,7 @@ static int env_flash_load(void)
 		     "reading environment; recovered successfully\n\n");
 #endif /* CONFIG_ENV_ADDR_REDUND */
 
-	return env_import((char *)flash_addr, 1);
+	return env_import((char *)flash_addr, 1, H_EXTERNAL);
 }
 #endif /* LOADENV */