target/ppc: return a nil HPT base address on sPAPR machines

commit e57ca75ce3 ("target/ppc: Manage external HPT via virtual
hypervisor") exported a set of methods to manipulate the HPT from the
core hash MMU. But SPR_SDR1 is still used under some circumstances to
get the base address of the HPT, which is incorrect for the sPAPR
machines.

Only the logging should be impacted.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

target/ppc/mmu-hash64.h

@@ -102,6 +102,9 @@ void ppc_hash64_finalize(PowerPCCPU *cpu);
 
 static inline hwaddr ppc_hash64_hpt_base(PowerPCCPU *cpu)
 {
+    if (cpu->vhyp) {
+        return 0;
+    }
     return cpu->env.spr[SPR_SDR1] & SDR_64_HTABORG;
 }