get_processor_name should use /proc/device-tree/model when /proc/cpuinfo does not contain 'model name'

[b-morgan]

Is your feature request related to a problem? Please describe.
With Debian 11 or 12 on an Orange Pi 3B (Rockchip RK3566 OPi 3B) and a Libre Le Potato (Libre Computer AML-S905X-CC) /proc/cpuinfo does not contain a "model name". However, /proc/device-tree/model contains a useful string.

Describe the solution you'd like
Return /proc/device-tree/model when /proc/cpuinfo does not contain a "model name"