env: nand: Put ENV_INVALID into gd->env_valid if default environment

env_nand_init() says the environment is valid even if it is assigning
default environment due to not being able to access nand pre-reloaction
(determined by macro values). Change this to ENV_INVALID and let the
generic env_init() function, which calls this initializer, assign the
default environment.
Signed-off-by: NMarek Behún <marek.behun@nic.cz>
Reviewed-by: NSimon Glass <sjg@chromium.org>

env/nand.c

@@ -107,8 +107,7 @@ static int env_nand_init(void)
 	gd->env_addr = (ulong)env_ptr->data;
 
 #else /* ENV_IS_EMBEDDED || CONFIG_NAND_ENV_DST */
-	gd->env_addr	= (ulong)&default_environment[0];
-	gd->env_valid	= ENV_VALID;
+	gd->env_valid	= ENV_INVALID;
 #endif /* ENV_IS_EMBEDDED || CONFIG_NAND_ENV_DST */
 
 	return 0;