commit aac5c4226e upstream.
If kvm_io_bus_register_dev() fails then it returns success but it should
return an error code.
I also did a little cleanup like removing an impossible NULL test.
Fixes: 2b3c246a68 ('KVM: Make coalesced mmio use a device per zone')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>