By Munsif Vengattil and Aditya Kalra NEW DELHI (Reuters) -India’s Tata Electronics has agreed to buy a majority stake in Taiwanese contract manufacturer Pegatron’s only iPhone plant in India, forming a new joint venture that strengthens Tata’s position as an Apple (NASDAQ:) supplier, two sources told Reuters. Under the deal announced internally last week, Tata will hold 60% and run daily operations under the joint venture, while Pegatron will hold