Resurrect dmasound:
  - Re-add dmasound to the build process
  - Update dmasound.h, which got missed in the dmasound update in 2.5.15
  - Compile fixes for core, Atari, Amiga Paula, and Q40:
      o Update for s/MINOR/minor/g changes
      o Add missing <linux/interrupt.h>
      o Fix spinlock typo