env: flash: Cosmetic fix

Change tab to space in env_flash_init().

Signed-off-by: Marek BehĂșn <marek.behun@nic.cz>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/env/flash.c b/env/flash.c
index b3230fd..9c8abfa 100644
--- a/env/flash.c
+++ b/env/flash.c
@@ -228,7 +228,7 @@
 		return 0;
 	}
 
-	gd->env_valid	= ENV_INVALID;
+	gd->env_valid = ENV_INVALID;
 	return 0;
 }
 #endif