testing/dovi-tool: upgrade to 2.1.2, enable on loongarch64

https://github.com/quietvoid/dovi_tool/releases/tag/2.1.2
https://github.com/quietvoid/dovi_tool/releases/tag/2.1.1
https://github.com/quietvoid/dovi_tool/releases/tag/2.1.0

Also resolves a rebuild error with time crate and rust >=1.80.

cc: @team/rust