Added Qt touchscreen library (Tslib) to the build

Symbol: BR2_PACKAGE_QT_MOUSE_TSLIB [=y]
Type  : boolean
Prompt: tslib
  Defined at package/qt/Config.mouse.in:12
  Depends on: BR2_PACKAGE_QT [=y] && BR2_PACKAGE_QT_GUI_MODULE [=y]
  Location:
    -> Package Selection for the target
      -> Graphic libraries and applications (graphic/text)
        -> Qt (BR2_PACKAGE_QT [=y])
          -> Mouse drivers