usb: rockchip: fix command failed on host side due to missing data

Two consecutive rockusb_tx_write without waiting for request complete
do results in transfer reset of first request and thus no or incomplete
data transfer. This because rockusb_tx_write do use just one USB request
to keep serialization.

So calls like:
rockusb_tx_write_str(emmc_id);
rockusb_tx_write_csw(cbw->tag, cbw->data_transfer_length, CSW_GOOD);

was succeeding only when DEBUG was defined because the time spent
printing debug info was enough for transfer to complete.

This patch fixes the issue adding a simple request complete handler
called rockusb_tx_write_csw to be set as complete handler of in_req
when sending back simple payload + CSW replies to commands.

This new handler will always send CSW_GOOD replies because in case
of error the command callback itself must send back an error CSW as
unique reply to command.

This patch fixes execution of:
$ rkdeveloptool rfi
when DEBUG is not defined.

Signed-off-by: Alberto Panizzo <alberto@amarulasolutions.com>