python-scripts: Hacks in nxdk-rdt interface

[JayFoxRox]

nxdk-rdt is still horribly broken so it has a hack to split larger writes into smaller chunks.
The hack should be removed once nxdk-rdt has been improved. See https://github.com/mborgerson/nxdk-rdt/issues/5

Additionally the play_ac97.py can only be ran once as a result of this (further writes will break the nxdk-rdt network code).