sepolicy: add sepolicy for usta_app to open system_data_file

The error is encountered when usta_app is trying to open system_data_file.

Addressing the issue:
avc: denied { open } for comm="RenderThread" path="/data/misc/gpu/adreno_config.txt"
dev="dm-0" ino=1180432 scontext=u:r:usta_app:s0 tcontext=u:object_r:system_data_file:s0
tclass=file permissive=1The error is encountered when usta_app is trying to open system_data_file.

Change-Id: I1398fa111a0c0713bddd6bb1b2fc1e05cf972533