KVM: PPC: Fix stbux emulation

Stbux writes the address it's operating on to the register specified in ra,
not into the data source register.
Signed-off-by: Alexander Graf <agraf@suse.de>

arch/powerpc/kvm/emulate.c

@@ -229,7 +229,7 @@ int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
 			emulated = kvmppc_handle_store(run, vcpu,
 						       kvmppc_get_gpr(vcpu, rs),
 			                               1, 1);
-			kvmppc_set_gpr(vcpu, rs, vcpu->arch.vaddr_accessed);
+			kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
 			break;
 
 		case OP_31_XOP_LHAX: