tools: rimage: return a negative error code from elf_error()

elf_error() negates its argument, so an already negative code was turned
into a positive value that callers testing "ret < 0" take for success.

Signed-off-by: Adrian Bonislawski <adrian.bonislawski@intel.com>

Author: abonislawski

tools/rimage/src/elf_file.c

@@ -95,13 +95,13 @@ static struct name_val p_flags[] = {
  * 
  * @param elf elf file structure
  * @param msg error message
- * @param error error code to return
- * @return error code
+ * @param error positive errno value, or an already negative error code
+ * @return negative error code
  */
 static int elf_error(const struct elf_file *elf, const char *msg, int error)
 {
 	fprintf(stderr, "Error: %s: %s\n", elf->filename, msg);
-	return -error;
+	return error < 0 ? error : -error;
 }
 
 /**