Simplify interface of write_selected_tx_size and read_tx_size

Change-Id: Ia2b2a895deefaaf7b34bf26df86add56dbab082c
vp8 quantize is now in intrinsics, not asm

Change-Id: Ie106c5335c9ba5aac81e23150e7026fb6ea6196e
Merge "Simplify interface of write_selected_tx_size and read_tx_size"
Merge "vp8 quantize is now in intrinsics, not asm"