[llvm-readobj] Little clean up inside parseDynamicTable
This anoymous function actually has same logic with Obj->toMappedAddr.
Besides, I have a question on resolving illegal value. gnu-readelf, gnu-objdump and llvm-objdump could parse the test file 'test/tools/llvm-objdump/Inputs/private-headers-x86_64.elf', but llvm-readobj will fail when parse DT_RELR segment. Because, the value is 0x87654321 which is illegal. So, shall we do this clean up rather then remove the checking statements inside anoymous function?
if (Delta >= Phdr.p_filesz) return createError("Virtual address is not in any segment");
Reviewers: rupprecht, jhenderson
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D55329