spapr: nested: Initialize the GSB elements lookup table.

spapr: nested: Initialize the GSB elements lookup table.

Nested PAPR API provides a standard Guest State Buffer (GSB) format
with unique IDs for each guest state element for which get/set state is
supported by the API. Some of the elements are read-only and/or guest-wide.
Introducing additional required GSB elements and helper routines for state
exchange of each of the nested guest state elements for which get/set state
should be supported by the API.

[amachhiw: set the PCR whenever logical PVR is set]

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
Signed-off-by: Amit Machhiwal <amachhiw@linux.vnet.ibm.com>
Signed-off-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>