Change the od_encode_band_pvq_splits() and od_encode_pvq_split()
 functions to take an aom_writer struct instead of an od_ec_enc struct.
Rename od_encode_band_pvq_splits() to aom_encode_band_pvq_splits() and
 od_encode_pvq_split() to aom_encode_pvq_split().

Change-Id: I72e6684e032f4c8f9f9133c6102f870830001712