Switch MtpFfsHandle to aio, add control functions.

MtpFfsHandle now uses kaio to handle usb data.
This achieves better performance without using
the endpoint alloc ioctl.

This also allows ep0 events to be handled without
race conditions. Events will also include control
requests, which will allow both host and device
initiated cancellation.

Bug: 37916658
Bug: 36802721
Test: Transfer various size files, run MtpFfsHandleTest
Test: Cancel transfer on Windows
Test: Allow device to cancel transfer on Windows
Change-Id: Ib3ce996f00782ce7f68f29b2510dbc17f09fdf14