ALSA: firewire-motu: parse messages for line input parameters in register DSP model

This commit parses message and cache current parameters of line input
function, available for MOTU 828 mk2 and Traveler.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20211015080826.34847-8-o-takashi@sakamocchi.jp


Signed-off-by: Takashi Iwai <tiwai@suse.de>