kvm: use kmalloc() instead of kzalloc() during iodev register/unregister

All fields of kvm_io_range were initialized or copied explicitly
afterwards. So switch to use kmalloc().

Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

virt/kvm/kvm_main.c

@@ -3341,7 +3341,7 @@ int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
 	if (bus->dev_count - bus->ioeventfd_count > NR_IOBUS_DEVS - 1)
 		return -ENOSPC;
 
-	new_bus = kzalloc(sizeof(*bus) + ((bus->dev_count + 1) *
+	new_bus = kmalloc(sizeof(*bus) + ((bus->dev_count + 1) *
 			  sizeof(struct kvm_io_range)), GFP_KERNEL);
 	if (!new_bus)
 		return -ENOMEM;
@@ -3373,7 +3373,7 @@ int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
 	if (r)
 		return r;
 
-	new_bus = kzalloc(sizeof(*bus) + ((bus->dev_count - 1) *
+	new_bus = kmalloc(sizeof(*bus) + ((bus->dev_count - 1) *
 			  sizeof(struct kvm_io_range)), GFP_KERNEL);
 	if (!new_bus)
 		return -ENOMEM;