irq: fix memory leak

entry is moved from list but is not freed.
Signed-off-by: Nlinzhecheng <linzhecheng@huawei.com>

Message-Id: <20171225024704.19540-1-linzhecheng@huawei.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

target/i386/kvm.c

@@ -3470,6 +3470,7 @@ int kvm_arch_release_virq_post(int virq)
         if (entry->virq == virq) {
             trace_kvm_x86_remove_msi_route(virq);
             QLIST_REMOVE(entry, list);
+            g_free(entry);
             break;
         }
     }