usb: usb_test.sh: Improve throughput accuracy

Use the time returned by testusb instead of measuring our own
time as that is more accurate and doesn't include time required
for searching for the test USB device. This produces more accurate
throughput measurements.

Signed-off-by: Roger Quadros <rogerq@ti.com>
usb: usb_test.sh: Improve test parameters for better throughput

These parameters give a better throughput measurement.

Signed-off-by: Roger Quadros <rogerq@ti.com>
usb: usb_perf_raw: Reload necessary modules with appropriate parameters

Parameters are suited for better throughput measurements.

Signed-off-by: Roger Quadros <rogerq@ti.com>
usb: usb_perf_raw: Add ISO performance tests

Add iso-out-perf and iso-in-perf tests for ISO performance
measurement in the usb_test.sh utility.

Add USB_L_PERF_ISO_OUT and USB_L_PERF_ISO_IN test cases
for USB ISO performance.

Signed-off-by: Roger Quadros <rogerq@ti.com>
usb: usb_perf_raw: Check for CONFIG_USB_TEST and CONFIG_USB_ZERO

We need the USB_TEST and USB_ZERO drivers to be present as modules
since we need to reload it with different module parameters for different
test cases.

Signed-off-by: Roger Quadros <rogerq@ti.com>
usb: usb_stress_io: Reload necessary modules with appropriate parameters

Some tests like ISO need specific parameters for the usbtest module so
we reload the modules with the necessary parameters.

Check if USB_TEST and USB_ZERO drivers are configured as modules since we
need to load to load them with different parameters for different test cases.

Increase USB_L_STRESS_UNLINK timeout to 200 seconds.

get rid of XHCI* test cases as it adds no differentiation at the moment.

Signed-off-by: Roger Quadros <rogerq@ti.com>