[llvm-readobj/elf] - Refine the warning about the broken PT_DYNAMIC segment.

Splitted out from D85519.

Currently we report "PT_DYNAMIC segment offset + size exceeds the size of the file",
this changes it to
"PT_DYNAMIC segment offset (0x1234) + file size (0x5678) exceeds the size of the file (0x68ab)"

Differential revision: https://reviews.llvm.org/D85654