Add missing free call

The summary pointer is not being freed after returning from
the default case in the switch statement.
Added a call to free the summary pointer before returning.

Author: BenReed161

lib/fw.c

@@ -1601,6 +1601,7 @@ switchtec_fw_part_summary(struct switchtec_dev *dev)
 		break;
 	default:
 		errno = EINVAL;
+		free(summary);
 		return NULL;
 	}