Disable use of libinput in imx6

Currently libinput does not work with nitrogen6x and touchscreen,
so disable it until problem is resolved.

Change-Id: I5c569f843fbc958faed9da3bd3879aa66efeb5f5
Task-number: QTEE-1032
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>
Reviewed-by: Teemu Holappa <teemu.holappa@theqtcompany.com>

recipes-qt/b2qt-addons/b2qt-appcontroller/mx6/appcontroller.conf

@@ -4,4 +4,5 @@ env=QT_IM_MODULE=qtvirtualkeyboard
 env=QT_QPA_EVDEV_TOUCHSCREEN_PARAMETERS=/dev/input/event0
 env=QT_GSTREAMER_CAMERABIN_VIDEOSRC=mxc_v4l2=mfw_v4lsrc,v4l2src
 env=QT_QUICK_CONTROLS_STYLE=Flat
+env=QT_QPA_EGLFS_NO_LIBINPUT=1
 base=linux