USB: Fix makefile so that CONFIG_WDM and CONFIG_TMC work.

If CONFIG_USB_ACM and CONFIG_USB_PRINTER are not set, then
cdc-wdm and usbtmc won't get built.
Signed-off-by: Andy Lutomirski <amluto@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/Makefile

@@ -27,6 +27,8 @@ obj-$(CONFIG_USB_WUSB)		+= wusbcore/
 
 obj-$(CONFIG_USB_ACM)		+= class/
 obj-$(CONFIG_USB_PRINTER)	+= class/
+obj-$(CONFIG_USB_WDM)		+= class/
+obj-$(CONFIG_USB_TMC)		+= class/
 
 obj-$(CONFIG_USB_STORAGE)	+= storage/
 obj-$(CONFIG_USB)		+= storage/