Allow dumpstate to trace drm hals

Change-Id: Id7823a3130443107beb4d97426807a6395cf6930
related-to-bug:74607984
test:adb bugreport and check for drm trace dumps

public/dumpstate.te

@@ -73,6 +73,7 @@ allow dumpstate {
   hal_audio_server
   hal_bluetooth_server
   hal_camera_server
+  hal_drm_server
   hal_graphics_composer_server
   hal_sensors_server
   hal_vr_server