[yaml2obj/obj2yaml/llvm-readobj] Support printing and parsing AVR-specific e_flags

The `e_flags` contains a mixture of bitfields and regular ones, ensure all of them can be serialized and deserialized.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D100250

GitOrigin-RevId: 24185541ca48bd7ed089a4dbf57bdcb91e290508
5 files changed