usbd: don't leak the queued-setup counter when the event queue is full

A SETUP arriving while the event queue is full is silently dropped by
queue_event(), but _usbd_queued_setup has already been incremented. The
leaked count makes the event handler skip every subsequent SETUP
("Skipped since there is other SETUP in queue") forever: EP0 stays deaf
until tud_init() while the device otherwise looks alive - enumerated,
endpoints armed. Undo the increment when the enqueue fails.

Unit test: fill the queue so a SETUP is dropped, then verify the next
SETUP still completes a GET_DESCRIPTOR control transfer.

0 files changed, 0 insertions, 0 deletions