Fix the build in c++11 mode.

The errors were:

non-constant-expression cannot be narrowed from type 'int64_t' (aka 'long') to 'uint32_t' (aka 'unsigned int') in initializer list

and

non-constant-expression cannot be narrowed from type 'long' to 'uint32_t' (aka 'unsigned int') in initializer list

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182168 91177308-0d34-0410-b5e6-96231b3b80d8
Convert obj2yaml to use yamlio.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182169 91177308-0d34-0410-b5e6-96231b3b80d8