KVM: fix fault page leak

fault_page is forgot to be freed

Signed-off-by: Xiao Guangrong <[e-mail]>
Signed-off-by: Marcelo Tosatti <[e-mail]>

virt/kvm/kvm_main.c

···
 	kvm_arch_hardware_unsetup();
 	kvm_arch_exit();
 	free_cpumask_var(cpus_hardware_enabled);
+	__free_page(fault_page);
 	__free_page(hwpoison_page);
 	__free_page(bad_page);
 }