dreambox-secondstage: generate flash binary on the build system

No need to do this runtime on the target, abusing
mtd_debug to find the flash parameters, we have all
the information we need on the build host.

As a result, we no longer need the 'buildimage' binary
on the target, saving a bit of image size.

Also, keep the secondstage binary in /tmp, no need to
keep it around after we're done; saving a bit more
rootfs space.

Use 'flash_erase' to erase the mtd partition,
that's what it's for.

And finally, there is no need to sync the filesystems
after nandwrite.
dreambox-secondstage: deploy secondstage bin in DEPLOY_DIR_IMAGE
dreambox-secondstage: bump PR
add Henksat Ziggo regio 1111 settings
dreambox-secondstage-base: create DEPLOY_DIR_IMAGE if it does not exist

DEPLOY_DIR_IMAGE is not created untill image.do_rootfs
So when doing a clean build, we need to create it ourselves.

No need for a PR bump, this issue does not affect
existing builds, and has no effect on the resulting package
contents.
dreambox-nand-64mb: decrease favor_lzo percentage

On devices with such limited flash size, we cannot
afford to favor lzo, unless there is less than 1%
advantage in compression ratio.
linux-dreambox: do not keep /boot mounted after kernel-image update
follow dreambox boot mtd partition name change
Merge remote-tracking branch 'openpli3/master' into HEAD