fit_image: Fix a double close() on the error path

There is an extra close() call which is not needed.

Reported-by: Coverity (CID: 143065)
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/fit_image.c b/tools/fit_image.c
index ddefa72..0551572 100644
--- a/tools/fit_image.c
+++ b/tools/fit_image.c
@@ -343,7 +343,6 @@
 	if (ret != size) {
 		fprintf(stderr, "%s: Can't write %s: %s\n",
 			params->cmdname, fname, strerror(errno));
-		close(fd);
 		goto err;
 	}
 	close(fd);