Grant permission for mediatranscoding hal_allocator for OMX platforms

This is a port of If44653f436d4e5dcbd040af24f03b09ae8e7ac05 which
made this change to prebuilts/api/31.0/private/mediatranscoding.te.

This is required to pass CTS test.

Test: run cts -m CtsMediaTranscodingTestCases -t android.media.mediatranscoding.cts.MediaTranscodingManagerTest#testAddingClientUids
Bug: 207821225
Bug: 213141904
Change-Id: Iefe9f326572976e230eeeec74e612b6e20b31887
2 files changed