phb4: Additional RXE_ARB: DEC Stage Valid Error fix
phb4: Additional RXE_ARB: DEC Stage Valid Error fix

In this recent fix:
  8b4c7a3cef phb4: Mask RXE_ARB: DEC Stage Valid Error
We worked around a problem but the workaround wasn't complete.

Now that we have full documentation and details on the issue, we have
additional registers we need to change inits on.

Signed-off-by: Michael Neuling <7b0ab45a730e48a69239010b5b8fe5fa4e8eaac6@neuling.org>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

qemu/skiboot,legoater/skiboot,shenki/skiboot,stewart-ibm/skiboot,open-power/skiboot,shenki/skiboot,qemu/skiboot,shenki/skiboot,legoater/skiboot,open-power/skiboot,open-power/skiboot,stewart-ibm/skiboot,qemu/skiboot,shenki/skiboot,shenki/skiboot,legoater/skiboot,legoater/skiboot,qemu/skiboot,open-power/skiboot,legoater/skiboot,stewart-ibm/skiboot,open-power/skiboot,qemu/skiboot