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

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

The convert_chmap_v3() has a loop with its increment size of
cs_desc->wLength, but we forgot to validate cs_desc->wLength itself,
which may lead to potential endless loop by a malformed descriptor.

Add a proper size check to abort the loop for plugging the hole.

Fixes: ecfd41166b72 ("ALSA: usb-audio: Validate UAC3 cluster segment descriptors")
Cc: <stable@vger.kernel.org>
Link: https://patch.msgid.link/20260427152224.15276-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>