The als4000 driver is for Avance Logic ALS4000 sound card.

This driver is referred to Minix(3.4.0) es1371 driver, 
Linux(4.2.1) snd_als4000 driver and ALS4000 Media Audio Specification(Rev 1.0).

Revision 1.0 2016/12/16
Authored by Jia-Ju Bai <baijiaju1990@163.com>

Something can be improved: 
1. MIDI and MPU-401 ports are not supported.
2. Only supported 8 and 16 sample bits, and common sample rates (like 44100).
3. Multiple music files may not be played well at the same time.
