firewire: core: fix race condition against transaction list

firewire: core: fix race condition against transaction list

The list of transaction is enumerated without acquiring card lock when
processing AR response event. This causes a race condition bug when
processing AT request completion event concurrently.

This commit fixes the bug by put timer start for split transaction
expiration into the scope of lock. The value of jiffies in card structure
is referred before acquiring the lock.

Cc: stable@vger.kernel.org # v6.18
Fixes: b5725cfa4120 ("firewire: core: use spin lock specific to timer for split transaction")
Reported-by: Andreas Persson <andreasp56@outlook.com>
Closes: https://github.com/alsa-project/snd-firewire-ctl-services/issues/209
Tested-by: Andreas Persson <andreasp56@outlook.com>
Link: https://lore.kernel.org/r/20260127223413.22265-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>