[ck] Add Shuai Xue as perf subsystem maintainer

I'm glad to invide Shuai Xue <xueshuai(a)linux.alibaba.com> to be a maintainer of ANCK perf subsystem. Shuai is working on linux perf subsystem for 2 years, and show great interest in kernel technologies. Here are some highlight contributions from Shuai: 1. Design and implement CMN, DDR and PCIe PMU driver for performance monitor, and is Alibaba PMU maintainer in Linux community now. 2. Design and verify synthetic events with tools/perf for functional debugging to facilitate system maintenance and support the wide application of these events. 3. Backport and enable SPE features for perf-mem, perf-c2c and perf-spe-c2c and apply SPE to optimise application performance, e.g. SPECjbb2015. 4. Proficient in problem analysis, and skilled at using ftrace, kprobe, tracepoint,PMU, etc. Working with Shuai is efficient and makes a sense of achievement. Let us hope it to happen soon.