remove un-needed setdir functions add bus_teardown_intr calls where necessary destroy our dma tags where necessary destroy ac97 before releasing resources
change channel interface - kobj implementation coming soonish make pcm_makelinks not panic if modular add pcm_unregister() these changes support newpcm kld unloading, but this is only implemented by ds1.c
PR: conf/20698 Submitted by: dimmy the wild <diwil@dataart.com>