KVM: Return -ENOTTY on unrecognized ioctls

Not the incorrect -EINVAL.

Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 2a4551f..95af622 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -421,7 +421,7 @@
 
 	switch (ioctl) {
 	default:
-		r = -EINVAL;
+		r = -ENOTTY;
 	}
 
 	return r;