[clang] [HLSL] Fix resrouce wrapper declaration (PR #129100)

[Steven Perron via cfe-commits]

s-perron wrote:

I created a new PR to make the resource wrappers static. @hekota Was right. Not much needed to change in codegen. We were already initializing all global (internal or external) that have the resource binding attribute. I must have been testing the wrong examples when I said codegen would have to change significantly.

https://github.com/llvm/llvm-project/pull/129100