MdeModulePkg: The patch eliminates two assumptions

MdeModulePkg: The patch eliminates two assumptions
1) XHCI host controller hw always provides more than 5 interrupters.
Now using interrupter 0 to accommodate all received events.
2) XHCI host controller hw always provides 32bytes context size.
Now it dynamically detect context size and construct it.

also solved several issues:
1) Divides 64byte width register access to two 32bit registers access because some XHCI chipsets cannot support a single 64bit access.
2) Remove halt host controller statement in UsbBusDriverBindingStop(). It has been done by host controller’s DriverBindingStop(). And XhciDriverBindingStop() need XHCI host controller is in running state because it need execute DISABLE_SLOT cmd to release h/w resource.

signed-off-by: erictian
Reviewed-by: li-elvin
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12785 6f19259b-4bc3-4df7-8a09-765794883524