XHCI: The root hub address is always 1.

AllocateAddress() is the pre-USB3 way of doing things;
as we never use it anywhere else and it is specific to
each BusManager, we always just got 1, which is what
the root hub will always be anyway.

Additionally, clarify the logic in _InsertEndpointForPipe
that is special-casing the root hub.

No functional change intended.

src/add-ons/kernel/busses/usb/xhci.cpp

@@ -201,7 +201,6 @@ XHCI::XHCI(pci_info *info, Stack *stack)
 		fCmdCompSem(-1),
 		fStopThreads(false),
 		fRootHub(NULL),
-		fRootHubAddress(0),
 		fPortCount(0),
 		fSlotCount(0),
 		fScratchpadCount(0),
@@ -664,8 +663,7 @@ XHCI::Start()
 		TRACE_ERROR("HCH start up timeout\n");
 	}
 
-	fRootHubAddress = AllocateAddress();
-	fRootHub = new(std::nothrow) XHCIRootHub(RootObject(), fRootHubAddress);
+	fRootHub = new(std::nothrow) XHCIRootHub(RootObject(), 1);
 	if (!fRootHub) {
 		TRACE_ERROR("no memory to allocate root hub\n");
 		return B_NO_MEMORY;
@@ -693,7 +691,7 @@ status_t
 XHCI::SubmitTransfer(Transfer *transfer)
 {
 	// short circuit the root hub
-	if (transfer->TransferPipe()->DeviceAddress() == fRootHubAddress)
+	if (transfer->TransferPipe()->DeviceAddress() == 1)
 		return fRootHub->ProcessTransfer(this, transfer);
 
 	TRACE("SubmitTransfer(%p)\n", transfer);
@@ -1705,10 +1703,13 @@ XHCI::_InsertEndpointForPipe(Pipe *pipe)
 	}
 
 	Device* usbDevice = (Device *)pipe->Parent();
+	if (usbDevice->Parent() == RootObject()) {
+		// root hub needs no initialization
+		return B_OK;
+	}
+
 	struct xhci_device *device = (struct xhci_device *)
 		usbDevice->ControllerCookie();
-	if (usbDevice->Parent() == RootObject())
-		return B_OK;
 	if (device == NULL) {
 		panic("device is NULL\n");
 		return B_NO_INIT;

src/add-ons/kernel/busses/usb/xhci.h

@@ -252,7 +252,6 @@ private:
 
 			// Root Hub
 			XHCIRootHub *		fRootHub;
-			uint8				fRootHubAddress;
 
 			// Port management
 			uint8				fPortCount;