KVM: PPC: Book3S PR: Expose TAR facility to guest

POWER8 implements a new register called TAR. This register has to be
enabled in FSCR and then from KVM's point of view is mere storage.

This patch enables the guest to use TAR.

Signed-off-by: Alexander Graf <agraf@suse.de>

arch/powerpc/include/asm/kvm_host.h

@@ -449,7 +449,9 @@ struct kvm_vcpu_arch {
 	ulong pc;
 	ulong ctr;
 	ulong lr;
+#ifdef CONFIG_PPC_BOOK3S
 	ulong tar;
+#endif
 
 	ulong xer;
 	u32 cr;