fdtoverlay: Return non-zero exit code if overlays can't be applied

At present the tool terminates its execution if one of the overlays passed
as command-line arguments can't be successfully read or applied, but the exit
code of the process is zero, making failures hard to detect inside scripts.

Signed-off-by: Valter Minute <valter.minute@toradex.com>
Message-Id: <20191009123256.14248-1-valter.minute@toradex.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

fdtoverlay.c

@@ -110,7 +110,6 @@ static int do_fdtoverlay(const char *input_filename,
 			(unsigned long)buf_len, fdt_totalsize(blob));
 		goto out_err;
 	}
-	ret = 0;
 
 	/* allocate blob pointer array */
 	ovblob = xmalloc(sizeof(*ovblob) * argc);