tools: remove unused ret

Remove unused ret from fw_env_flush.

Signed-off-by: Jelle van der Waa <jelle@vdwaa.nl>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/env/fw_env.c b/tools/env/fw_env.c
index 18c2324..ca5507d 100644
--- a/tools/env/fw_env.c
+++ b/tools/env/fw_env.c
@@ -505,8 +505,6 @@
 
 int fw_env_flush(struct env_opts *opts)
 {
-	int ret;
-
 	if (!opts)
 		opts = &default_opts;