libaudiodriver: handle interrupt only once
libaudiodriver: handle interrupt only once

Apparently, qemu's sb16 doesn't reset the interrupt register
of the mixer and the driver ends up in an endless loop when
playing a "multi-fragment" sample.

Change-Id: I47633b99a0d79ba201aec785da69fb3950e026bf

veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi