Allow gpuservice to read tracefs entries

Gpu service needs tracefs access to attach the BPF program
to the gpu_mem_total tracepoint for GPU memory tracking.

Bug: 208892266
Bug: 209513178
Bug: 214061655
Test: adb shell dumpsys gpu --gpumem
Change-Id: I10fd54544bee940313f3987247c1841101a9d03a
Merged-In: I10fd54544bee940313f3987247c1841101a9d03a