USB: Properly assign IDs to USB Bus Managers (HCI drivers).

Previously they would just get -1, as the BusManager class
would request their ID before they had been added to the Stack.
Now we add them to the stack inside ::Start(), rather than letting
the individual drivers do that just after ::Start(), and then assign
the ID there directly.

src/add-ons/kernel/bus_managers/usb/BusManager.cpp

@@ -14,7 +14,7 @@ BusManager::BusManager(Stack *stack)
 	:	fInitOK(false),
 		fStack(stack),
 		fRootHub(NULL),
-		fUSBID(fStack->IndexOfBusManager(this))
+		fUSBID((uint32)-1)
 {
 	mutex_init(&fLock, "usb busmanager lock");
 
@@ -253,6 +253,8 @@ BusManager::FreeDevice(Device *device)
 status_t
 BusManager::Start()
 {
+	fStack->AddBusManager(this);
+	fUSBID = fStack->IndexOfBusManager(this);
 	return B_OK;
 }
 

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

@@ -1216,8 +1216,10 @@ EHCI::AddTo(Stack *stack)
 			// the bus took it away
 			item = new(std::nothrow) pci_info;
 
-			bus->Start();
-			stack->AddBusManager(bus);
+			if (bus->Start() != B_OK) {
+				delete bus;
+				continue;
+			}
 			found = true;
 		}
 	}

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

@@ -647,8 +647,10 @@ OHCI::AddTo(Stack *stack)
 			// the bus took it away
 			item = new(std::nothrow) pci_info;
 
-			bus->Start();
-			stack->AddBusManager(bus);
+			if (bus->Start() != B_OK) {
+				delete bus;
+				continue;
+			}
 			found = true;
 		}
 	}

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

@@ -1923,8 +1923,10 @@ UHCI::AddTo(Stack *stack)
 			// the bus took it away
 			item = new(std::nothrow) pci_info;
 
-			bus->Start();
-			stack->AddBusManager(bus);
+			if (bus->Start() != B_OK) {
+				delete bus;
+				continue;
+			}
 			found = true;
 		}
 	}

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

@@ -864,8 +864,10 @@ XHCI::AddTo(Stack *stack)
 			// the bus took it away
 			item = new(std::nothrow) pci_info;
 
-			bus->Start();
-			stack->AddBusManager(bus);
+			if (bus->Start() != B_OK) {
+				delete bus;
+				continue;
+			}
 			found = true;
 		}
 	}