[Task]: standardize naming in Kernel/firmware upgrades

[squassina]

Task description

Depending on configuration we have both firmware and kernel in UPD001.

I'd like to have an agreement whether we should use one or another both in enable and disable messages.

I'll create a PR based on the discussions without problem.

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[Tearran]

Given that "firmware" typically refers to software stored in ROM or EEPROM and is closely tied to hardware, using "kernel" makes the purpose clearer, especially in contexts where updates or software layers are tied to system-level operations. Kernel is more universally recognized as the core of an operating system, making it a better fit for discussions involving upgrades or modifications in a standard system environment.