s390/setup: re-arrange memblock setup

- Avoid using ULONG_MAX in memblock_remove, it has no functional change
  but makes memblock_dbg output a range which makes sense.

- Actually finish memblock memory setup before doing amode31/cr/uv
  setup.

- Move memblock_dump_all() debug output after memblock memory setup is
  complete. This gives us final "memory" regions if they were trimmed
  due to addressing limits and still "physmem" regions as original info
  which came from mem_detect.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>