Support for USB communication abort.

[Jan Vesely]

This concerns mainly USB interrupt transfers, but can be useful for all 4 types.
Interrupt transfer won't end until there is a change in device status. All transfer may hang in case of faulty devices.

All communication should be aborted when endpoint is removed from hc driver and possibly an abort call should be added to USB hc interface.

[Jakub Jermář]

Fix merged in commit df6ded8c93d4c5e36bb3d1598f5b42fb5553ffe3:

commit df6ded8c93d4c5e36bb3d1598f5b42fb5553ffe3
Merge: f5e5f73a3 b2dca8de8
Author: Jakub Jermar <jakub@jermar.eu>
Date:   Wed Feb 28 17:06:42 2018 +0100

    Merge github.com:helenos-xhci-team/helenos
    
    This commit merges support for USB 3 and generally refactors, fixes,
    extends and cleans up the existing USB framework.
    
    Notable additions and features:
    
      * new host controller driver has been implemented to control various
        xHC models (among others, NEC Renesas uPD720200)
      * isochronous data transfer mode
      * support for explicit USB device removal
      * USB tablet driver