mailbox: mtk-cmdq-mailbox: Switch to __pm_runtime_put_autosuspend()

pm_runtime_put_autosuspend() will soon be changed to include a call to
pm_runtime_mark_last_busy(). This patch switches the current users to
__pm_runtime_put_autosuspend() which will continue to have the
functionality of old pm_runtime_put_autosuspend().

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>