The value of data block counter is not calculated for incoming packet
without CIP header. This commit fixes the bug.

Fixes: 947b437e ("ALSA: firewire-lib: unify packet handler for IR context")
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>