audio_device.c: fix strict-overflow warning with gcc >= 12

Fix the following error

~/libs/tinyusb/src/class/audio/audio_device.c:1493:23: error: assuming pointer wraparound does not occur when comparing P +- C1 with P +- C2 [-Werror=strict-overflow]
 1493 |         while (p_desc < p_desc_end)
      |                ~~~~~~~^~~~~~~~~~~~
compilation terminated due to -Wfatal-errors.