[USB CDC] Fix data might not be transmitted until more is written#5652

Merged

me-no-dev merged 2 commits intomasterfrom

bugfix/cdc_write_halt

Sep 15, 2021

Commits on Sep 9, 2021

Use Ringbuf for CDC write to improve responsiveness and throughput
me-no-dev
committed

Commits on Sep 15, 2021

Do not use tx_complete. It is not reliable
me-no-dev
committed