KVM: VMX: trivial: use BUG_ON

Use BUG_ON(x) rather than if(x) BUG();

The semantic patch that fixes this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@ identifier x; @@
-if (x) BUG();
+BUG_ON(x);

@@ identifier x; @@
-if (!x) BUG();
+BUG_ON(!x);
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

arch/x86/kvm/vmx.c

@@ -4115,8 +4115,7 @@ static int handle_exception(struct kvm_vcpu *vcpu)
 		error_code = vmcs_read32(VM_EXIT_INTR_ERROR_CODE);
 	if (is_page_fault(intr_info)) {
 		/* EPT won't cause page fault directly */
-		if (enable_ept)
-			BUG();
+		BUG_ON(enable_ept);
 		cr2 = vmcs_readl(EXIT_QUALIFICATION);
 		trace_kvm_page_fault(cr2, error_code);