Arch-rivals Qualcomm and MediaTek are both making plans to move to the 7nm process next year to drive down the power efficiency, size and cost of mobile and IoT chips. And both of them look set to rely on the same foundry, Taiwan’s TSMC. According to reports in South Korea, Qualcomm is planning to put most of its 7nm business TSMC’s way, having switched to Samsung as its main 10nm foundry. The companies are not commenting as yet, but if Qualcomm does return to its traditional foundry partner for 7nm, it will be a blow to Samsung’s growing business in this area. The report said Qualcomm started working on its 7nm Snapdragon system-on-chip using TSMC tools in the middle of…