mailbox: altera: shut down RX polling timer on channel teardown

The RX polling callback unconditionally rearms the timer after it
processes mailbox data.  altera_mbox_shutdown() uses
timer_delete_sync(), which waits for a running callback but does not
prevent that callback from rearming the timer after the deletion.

Use timer_shutdown_sync() for the final polling teardown so the timer
cannot be queued again while the mailbox channel is being released.
The timer is reinitialized with timer_setup() on a later channel startup,
so polling mode remains reusable.

Fixes: f62092f6d77d ("mailbox: Add Altera mailbox driver")
Cc: stable@vger.kernel.org
Assisted-by: Codex:GPT-5
Signed-off-by: Runyu Xiao <runyu.xiao@seu.edu.cn>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>

0 files changed, 0 insertions, 0 deletions