[llvm] [AMDGPU][LowerModuleLDS] Handle non-dynlds zero sized type (PR #84742)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> The default stance is usually that we're compiling something like C in which case the address of different objects need to be different. 

This isn't the case with 0 sized allocations, which I believe are all required to get the same address 

https://github.com/llvm/llvm-project/pull/84742