posinstall:gf_prepare_kernel.sh: Fix non-overlay case
If the overlay created by the gfxml2tdo tool cannot be applied the
devicetree.dtb
will not be created. In this case the raw platform
device tree should be appended to the kernel.
However, there was a mix-up in the paths and the platform dtb was not found. Fix this by moving the $MOUNTPOINT variable to the cat command and remove it from the $DEVICETREE_APPEND_FILE in case of a successful overlay.
BCS 746-000150