ALSA: firewire-lib: pool sequence of packet in IT context independently

ALSA: firewire-lib: pool sequence of packet in IT context independently

Current implementation pools the sequence in AMDTP domain. This is convenient
regarding to memory usage and computation time, however inconvenient for the
devices such that several rx streams are expected to transfer timing
information independently.

This commit refactors to pool the sequence per rx packet stream.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210522013303.49596-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>