GPTR/Overlays stage-1b support in xip_customize
GPTR/Overlays stage-1b support in xip_customize

- Enabled to poll Nimbus DD level with support for overlays
  in the XIP.
- Enabled to pass hw image with overlays section populated
  with dd levels.

Change-Id: I25e8c7b41bf4514b8c5484d54dc7b5af856f2402
Original-Change-Id: Ib7de3698ac103b34293115d0b4870afd0e617315
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/41407
Reviewed-by: Thi N. Tran <25a2bca7ae5a8ea03be09ca8d282480c08c13052@us.ibm.com>
Reviewed-by: Claus M. Olsen <2da381e13dc4aeb07a557ddfc89fbb05265c54a4@us.ibm.com>
Tested-by: Jenkins Server <8e3f934e4c44875bc48d33da3ea13d93ba9a233f@us.ibm.com>
Tested-by: PPE CI <dc75934ba5befb9221434e67a247b93aec46b36b@us.ibm.com>
Tested-by: Hostboot CI <52521565bd8ea18a2b112942dce4f4220a97c2c8@us.ibm.com>
Reviewed-by: Jennifer A. Stofer <ab93eca12e43608f33daa16a67357cd7b7e867ab@us.ibm.com>

open-power/hostboot,open-power/hostboot,open-power/hostboot,open-power/hostboot,open-power/hostboot