hal_graphics_allocator_default.te

hal_*_default daemons whose policy is in common/device-agnostic policy
are provided by the vendor image (see vendor/file_contexts). Thus,
their policy should also reside in the vendor image, rather than in
the system image. This means their policy should live in the vendor
subdirectory of this project.

Test: Device boots and appears to work
Bug: 34135607
Bug: 34170079
Change-Id: I6613e43733e03d4a3d4726f849732d903e024016