KVM: PPC: Enable use of secondary htab bucket

We had code to make use of the secondary htab buckets, but kept that
disabled because it was unstable when I put it in.

I checked again if that's still the case and apparently it was only
exposing some instability that was there anyways before. I haven't
seen any badness related to usage of secondary htab entries so far.

This should speed up guest memory allocations by quite a bit, because
we now have more space to put PTEs in.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/powerpc/kvm/book3s_64_mmu_host.c

@@ -257,16 +257,9 @@ map_again:
 
 	if (ret < 0) {
 		/* If we couldn't map a primary PTE, try a secondary */
-#ifdef USE_SECONDARY
 		hash = ~hash;
+		vflags ^= HPTE_V_SECONDARY;
 		attempt++;
-		if (attempt % 2)
-			vflags = HPTE_V_SECONDARY;
-		else
-			vflags = 0;
-#else
-		attempt = 2;
-#endif
 		goto map_again;
 	} else {
 		int hpte_id = kvmppc_mmu_hpte_cache_next(vcpu);