pseries: Remove spapr_create_fdt_skel()

pseries: Remove spapr_create_fdt_skel()

For historical reasons construction of the guest device tree in spapr is
divided between spapr_create_fdt_skel() which is called at init time, and
spapr_build_fdt() which runs at reset time.  Over time, more and more
things have needed to be moved to reset time.

Previous cleanups mean the only things left in spapr_create_fdt_skel() are
the properties of the root node itself.  Finish consolidating these two
parts of device tree construction, by moving this to the start of
spapr_build_fdt(), and removing spapr_create_fdt_skel() entirely.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>