KVM: PPC: Implement extension to report number of memslots

QEMU assumes 32 memslots if this extension is not implemented. Although,
current value of KVM_USER_MEM_SLOTS is 32, once KVM_USER_MEM_SLOTS
changes QEMU would take a wrong value.
Signed-off-by: NNikunj A Dadhania <nikunj@linux.vnet.ibm.com>
Reviewed-by: NThomas Huth <thuth@redhat.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

arch/powerpc/kvm/powerpc.c

@@ -559,6 +559,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 		else
 			r = num_online_cpus();
 		break;
+	case KVM_CAP_NR_MEMSLOTS:
+		r = KVM_USER_MEM_SLOTS;
+		break;
 	case KVM_CAP_MAX_VCPUS:
 		r = KVM_MAX_VCPUS;
 		break;