KVM: PPC: Book3S PR: Fix compilation without CONFIG_ALTIVEC

Commit 9d1ffdd8 ("KVM: PPC: Book3S PR: Don't corrupt guest state
when kernel uses VMX") added a call to kvmppc_load_up_altivec() that
isn't guarded by CONFIG_ALTIVEC, causing a link failure when building
a kernel without CONFIG_ALTIVEC set.  This adds an #ifdef to fix this.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAlexander Graf <agraf@suse.de>

arch/powerpc/kvm/book3s_pr.c

@@ -619,8 +619,10 @@ static void kvmppc_handle_lost_ext(struct kvm_vcpu *vcpu)
 
 	if (lost_ext & MSR_FP)
 		kvmppc_load_up_fpu();
+#ifdef CONFIG_ALTIVEC
 	if (lost_ext & MSR_VEC)
 		kvmppc_load_up_altivec();
+#endif
 	current->thread.regs->msr |= lost_ext;
 }