firmware-security: Hide the panel when chassis type is an empty string
When requesting the chassis type through systemd-hostnamed, it sometimes returns an empty string "" not the "vm" to present the virtual machine. Since this panel will not be shown in the VM environment, if systemd-hostnamed returns an empty string or "vm", the panel will be hidden.
Fixes: #2016 (closed)
Signed-off-by: Kate Hsuan hpa@redhat.com