ALSA: firewire-lib: start processing content of packet at the same cycle in several IR contexts

DICE ASICs support several pairs of isochronous packet streaming. It's
convenient for drivers to process content of the packet in the same cycle
timing.

This commit adds structure member to manage the cycle to start
processing packet in several IR contexts. The cycle is decided in the
first callback of the IR contexts. The content of packet is dropped
till the cycle.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210520040154.80450-5-o-takashi@sakamocchi.jp


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