x86/l1tf: Fix build error seen if CONFIG_KVM_INTEL is disabled

allmodconfig+CONFIG_INTEL_KVM=n results in the following build error.

  ERROR: "l1tf_vmx_mitigation" [arch/x86/kvm/kvm.ko] undefined!

Fixes: 5b76a3cff011 ("KVM: VMX: Tell the nested hypervisor to skip L1D flush on vmentry")
Reported-by: Meelis Roos <mroos@linux.ee>
Cc: Meelis Roos <mroos@linux.ee>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/kernel/cpu/bugs.c

@@ -664,10 +664,9 @@ void x86_spec_ctrl_setup_ap(void)
 enum l1tf_mitigations l1tf_mitigation __ro_after_init = L1TF_MITIGATION_FLUSH;
 #if IS_ENABLED(CONFIG_KVM_INTEL)
 EXPORT_SYMBOL_GPL(l1tf_mitigation);
-
+#endif
 enum vmx_l1d_flush_state l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_AUTO;
 EXPORT_SYMBOL_GPL(l1tf_vmx_mitigation);
-#endif
 
 static void __init l1tf_select_mitigation(void)
 {