sound: ua101: fix division by zero at probe

In the Linux kernel, the following vulnerability has been resolved: sound: ua101: fix division by zero at probe Add a missing sanity check for bNrChannels in detect_usb_format() to prevent a division by zero in playback_urb_complete() and capture_urb_complete(). USB core does not validate class-specific descriptor fields such as bNrChannels, so drivers must verify them before use. If a device provides bNrChannels = 0, frame_bytes becomes zero and is later used as a divisor in the URB completion handlers, leading to a kernel crash.