colibri-vf: Fix added kernel modules

config_script only worked with the freescale kernel recipes, so
moving to do_configure_prepend.  Why must this be different for each
kernel recipe!

Change-Id: I21d2d6ca5912bb57c7cfdb08e5c084ec868336ba
Reviewed-by: Samuli Piippo <samuli.piippo@theqtcompany.com>

meta-toradex-extras/recipes/linux/linux-toradex-vf_3.18.bbappend

@@ -26,8 +26,8 @@ SRC_URI += " \
         file://0001-Enable-Fusion-7-and-10-multi-touch-controller.patch \
         "
 
-config_script () {
+do_configure_prepend () {
 	# FunctionFS for adb
-	echo "CONFIG_USB_FUNCTIONFS=m"  >> ${S}/.config
-	echo "TOUCHSCREEN_FUSION_F0710A=y" >> ${S}/.config
+	echo "CONFIG_USB_FUNCTIONFS=m"  >> ${WORKDIR}/defconfig
+	echo "TOUCHSCREEN_FUSION_F0710A=y" >> ${WORKDIR}/defconfig
 }