MediaTranscodingService: Add sepolicy for MediaTranscodingService.

Bug:145233472
Test: Build and flash the phone.
"adb shell dumpsys -l | grep media" shows media.transcoding service.

Change-Id: I48a42e7b595754989c92a8469eb91360ab6db7c6
diff --git a/private/mediatranscoding.te b/private/mediatranscoding.te
new file mode 100644
index 0000000..e0ad84c
--- /dev/null
+++ b/private/mediatranscoding.te
@@ -0,0 +1,3 @@
+typeattribute mediatranscoding coredomain;
+
+init_daemon_domain(mediatranscoding)