Add a ventana-img.gz compressed disk image to support
squashfs+ext4 on a block storage device such as USB/MMC/SATA.
The Ventana bootloader expects the bootscript to be
boot/6x_bootscript-ventana therefore we must create a bootfs
that matches this.
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
1f5f17798a