target/ppc: Add basic support for "new format" HPTE as found on POWER9

target/ppc: Add basic support for "new format" HPTE as found on POWER9

POWER9 (arch v3) slightly changes the HPTE format. The B bits move
from the first to the second half of the HPTE, and the AVPN/ARPN
are slightly shorter.

However, under SPAPR, the hypercalls still take the old format
(and probably will for the foreseable future).

The simplest way to support this is thus to convert the HPTEs from
new to old format when reading them if the MMU model is v3 and there
is no virtual hypervisor, leaving the rest of the code unchanged.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20190215170029.15641-8-clg@kaod.org>
[dwg: Moved function to .c since there was no real need for it in the .h]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>