ALSA: firewire-lib: check cycle continuity

Within devices supported by drivers in ALSA firewire stack, OXFW-based
devices and Fireface devices are known to skip isochronous cycle for
packet transmission. The former is due to the jumbo payload quirk. The
latter is due to vendor protocol in which empty packet is not
transferred in blocking mode.

Although nothing to do just for handling events of the packet, packet
continuity is necessarily for media clock recovery. This commit checks
whether any cycle is continue or not.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210518130048.146596-8-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>