Make sure we don't clobber our endpoint configuration by
double configuring an Rx or Tx buffer against it. Wait for
the completion of the previous operation before allowing
endpoint configuration again.
Upper (COM) layer was calling down into the HID layer before
the HID interface had been enabled. This was leading to
interacting with the endpoint Rx and Tx FIFOs prior to init.
The FIFO config was then being clobbered when we the USB IF
was eventually enabled.
HID driver was incorrectly giving back the HID interface
descriptor when asked for the HID descriptor. This should
let OP boards interact better with generic HID layer drivers
and also gives us nicer output in lsusb once the HID descriptor
is read.
