By Yuvraj Malik and Jane Lanhee Lee (Reuters) -Advanced Micro Devices Inc on Tuesday forecast third-quarter revenue slightly below Wall Street estimates, a signal of uncertainty that concerned some investors after the company stock made huge gains in July. AMD continued to show strong growth in the data center business, at the expense of its rival Intel, but the company cut its market forecast for personal computer sales and shares fell more than 5% after hours. “After the surprisingly challenging quarter that Intel had, a lot of eyes were closely watching to see what AMD did and, overall, the…