MLK-17312-1 usb: cdns3: gadget: prepare setup packet buffer before receiving it

MLK-17312-1 usb: cdns3: gadget: prepare setup packet buffer before receiving it

At current setup packet handling flow, the setup packet buffer
is only prepared after the controller receives the setup packet,
then stores it at its internal buffer, and trigger DESCMIS interrupt
(Transfer descriptor missing) to prepare TRB for it.

The shortcoming of this design is there is an extra DESCMIS interrupt,
and consume more time on enumeration process. As an improvement,
we parepare setup buffer beforehand, it is prepared at below situations:
- After bus reset has finished.
- For non-data stage setup transfers, prepare it before sending ACK for
status stage.
- For data stage setup transfers, prepare it after data stage but
before sending ACK for status stage.

Acked-by: Jun Li <jun.li@nxp.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>