adbd: tune USB read/write sizes and queue depths.

Reduce the operation sizes to sizes that are small enough that the
kernel will run the OOM killer to try to make them succeed. Compensate
for the smaller operation sizes by increasing the queue depth.

Bug: http://b/126582877
Test: benchmark_device.py
Change-Id: I4d351f56c8f83fea882614238cc3fec8ba1e9bf9