Add a hack to ignore PCR bit for 6300ESB, 82801[D-G]B chips. It seems

Add a hack to ignore PCR bit for 6300ESB, 82801[D-G]B chips. It seems
that enabling busmastering would result in PCR bit ON after codec
reset.
While I'm here add DELAY(1) to codec access routine to give reasonable
time to codec operation. Without the delay, it would cause problems on
super-fast machines(> 2GHz). Also enable legacy audio for all 6300ESB,
82801[D-G]B chips. Previously, it enabled legacy audio for 82801DB(ICH4)
chip only.

Reported by:    Maxim Maximov mcsi AT mcsi DOT pp DOT ru
		Andrew Bliznak andriko.b AT gmail DOT com
Tested by:	brueffer, Maxim Maximov, Andrew Bliznak