usb: it82xx2: fix some issues related to extended endpoint enablement

This commit addresses some issues during the extended endpoint(ep
number is larger than 4) access. There are enable and ready bits for
each endpoint on the IT82xx2 chip. The transaction completion should be
determined by the ready and enable bits of the corresponding endpoint.
Additioinally, for non-control endpoint, the FIFO control register is
selected before writing data and cleared when the IN transaction is
completed. When an IN token interrupts, the FIFO control register
should be checked if it's selected to prevent fake tokens.

Tested with: Google spikyrock project

Signed-off-by: Ren Chen <Ren.Chen@ite.com.tw>