ALSA: usb-audio: Avoid potential endless loop in convert_chmap_v3()

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The vulnerability of the snd_hdac_regmap_sync() function in the sound/hda/hdac_regmap.c driver of the Linux High-Definition Audio kernel allows a hacker to cause a service failure.

The vulnerability of the sndhdacregmapsync function in the sound/hda/hdacregmap.c driver of the Linux High-Definition Audio kernel is related to the assignment of a null pointer. Exploiting this vulnerability could allow an attacker to cause a service failure...