KVM: PPC: Use CONFIG_PPC_BOOK3S define

Upstream recently added a new name for PPC64: Book3S_64.

So instead of using CONFIG_PPC64 we should use CONFIG_PPC_BOOK3S consotently.
That makes understanding the code easier (I hope).

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index 8ef3766..d864698 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig
@@ -31,7 +31,7 @@
 
 config KVM_BOOK3S_64
 	tristate "KVM support for PowerPC book3s_64 processors"
-	depends on EXPERIMENTAL && PPC64
+	depends on EXPERIMENTAL && PPC_BOOK3S_64
 	select KVM
 	select KVM_BOOK3S_64_HANDLER
 	---help---