add decode logic for cbo.* instructions in the decoder plugin

[liweiwei90]

[jamesbeyond]

Dear @liweiwei90

The CTG and ISAC Repo had been moved to riscv-arch-test via PR https://github.com/riscv-non-isa/riscv-arch-test/pull/495

If you think this PR is important, and need to me merged on to risc-v CTG or ISAC, please re-submit your PR against riscv-arch-test

This repository shall be archived in about one week time .