avicii: sepolicy: Allow kernel to read and write to block device

* 04-13 06:26:43.988   480   480 W kworker/7:4: type=1400
  audit(0.0:3137): avc: denied { read write } for name="sde67"
  dev="tmpfs" ino=15438 scontext=u:r:kernel:s0
  tcontext=u:object_r:block_device:s0 tclass=blk_file permissive=0