usb: misc: usbtest: add bulk queue test

The bulk queue tests are used to show 'best performance' for bulk
transfer, we are often asked this question by users. The implementation
is the same with iso test, that is queue request at interrupt completion,
so we reuse the iso structures, and rename them as common one.

It's result should be very close to IC simulation, in order
to get that, the device side should also need to prepare enough
queue.

We have got the 'best performance' (IN: 41MB, OUT: 39MB) at i.mx platform
(USB2, ARM Cortex A9, stream mode need to enable) with below command:

Host side:
modprobe usbtest
./testusb -a -t 27 -g 64 -s 16384
./testusb -a -t 28 -g 64 -s 16384
Gadget side:
modprobe g_zero loopdefault=1 qlen=64 buflen=16384

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Felipe Balbi <balbi@ti.com>