Clean up NVPTXLowerStructArgs.cpp. NFC

* Remove unnecessary const_casts and C-style casts
* Simplify attribute access code
* Simplify ArrayRef creation
* 80-col and clang-format



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221464 91177308-0d34-0410-b5e6-96231b3b80d8
[Hexagon] Adding basic Hexagon ELF object emitter.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221465 91177308-0d34-0410-b5e6-96231b3b80d8