classes: wic-helper: Add helper class for imx8 boards
classes: wic-helper: Add helper class for imx8 boards

Need to add two additional functions to do_wic_image_depends.
Without these the firmware-build is not finished but
the sdcard image is.

Signed-off-by: Janine Hagemann <8d93c2f2f444ad47da091bc753c1a540a7335a92@phytec.de>
Signed-off-by: Norbert Wesp <6da95d5bf7a9ae873d28e5fc932fdf5af58a5861@phytec.de>

PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec