Apple is asking its suppliers to manufacture between 70-80 million units of its upcoming two new iPhones combined by Dec. 30, The Wall Street Journal reports. As noted in the report, this represents a significant step up from last year’s initial order of 50-60 million units for the iPhone 5s and 5c. It still appears there could be a delay with the larger model, as display makers are “struggling to improve the production of the larger 5.5-inch…