This changes the s390 support on several stages:
1) On s390 the boot process is based on zipl which boots into an
initrd from which a userspace grub process is started to support
the grub capabilities. The implementation of this concept is
provided via the grub2-s390x-emu package. Once installed the
setup of the bootloader is done via the grub2-mkconfig and
grub2-install commands and therefore from a caller perspective
the same as with any other grub2 setup process. For kiwi this
means no extra zipl bootloader target code is needed. Therefore
this commit deletes the zipl setup from kiwi and puts on
the standard grub2 process. This Fixes bsc#1170863
2) To support different targettypes the grub2-s390x-emu provided
zipl template must be adapted. Parts of the former zipl bootloader
setup therefore now applies to an update of the zipl2grub
template file
3) Support for CDL/LDL DASD targets has been disabled in the schema
When testing 4k devices and a respective zipl2grub template
setup for CDL/LDL targettype it has turned out that grub2-install
is not able to run on such a device. My assumption is that
the device code in grub2-install does not work for 4k devices
with an fdasd created partition table. As this needs further
investigations and most probably adaptions on the grub toolchain
for s390, we disabled the setup of these modes for now.
emulated DASD (FBA) and SCSI targets stays supported.