ALSA: pcxhr: initialize mutexes before requesting threaded IRQ

In the Linux kernel, the following vulnerability has been resolved: ALSA: pcxhr: initialize mutexes before requesting threaded IRQ pcxhr_probe() requests pcxhr_threaded_irq() before initializing mgr->lock, even though the threaded handler takes that mutex. Initialize the manager locks before request_threaded_irq() so an early interrupt cannot run against uninitialized mutex state during probe.