KVM: VMX: Silence warning on 32-bit hosts

a is unused now on CONFIG_X86_32.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 54e732d..58badf1 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3602,7 +3602,9 @@
  */
 static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
 {
+#ifdef CONFIG_X86_64
 	unsigned long a;
+#endif
 	int i;
 
 	/* I/O */