[ALSA] add support for SB Live! 24-Bit External remote control

This patch rewrites the remote control code to use a table for
the peculiarities of the various SB models, and adds support
for a third model.

Signed-off-by: Raimonds Cicans <ray@vardes.lv>
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>