XHCI USB: Fixes.

* Add support for hubs in AllocateDevice().
* Prevent page fault in FinishTransfers().
* Set fCapabilityLength
* Correct in BIOS ownership code
* Fix context errors in _InsertEndpointForPipe().
* Update constants according to latest Specification (v1.1)
* Fix SMI code (reference
http://lkml.iu.edu/hypermail/linux/kernel/1204.2/02460.html).
* Fix Memory/Device-Slot leaks.
* Fix area allocation for TRBs.
* Fix for Intel Lynx Point and Panther Point chipsets. Also move init
of xhci before ehci, to switch USB 2.0 ports before the ehci module
discovers them.

Signed-off-by: Jérôme Duval <jerome.duval@gmail.com>
Revert unrelated part of 17aa359b5df69f658b4b33e29546c9fb2f0cfce3.