[llvm] [Hexagon] Define V91 ISA and Processor versions in ELF flags (PR #163631)

[via llvm-commits]

quic-areg wrote:

> Can you make corresponding changes in `ScalarBitSetTraits<ELFYAML::ELF_EF>::bitset()` in `llvm/lib/ObjectYAML/ELFYAML.cpp`?

https://github.com/llvm/llvm-project/pull/163824

https://github.com/llvm/llvm-project/pull/163631