[AMDGPU] Move getVGPREncodingGranule to TargetParser
Add GPUKind and SubArch encoding-granule queries with an explicit wave size.
Remove the BaseInfo counterpart and update codegen, assembler, and
disassembler callers, preserving kernel descriptor wave-size overrides.
Cover encoding granules across GPU generations and both wave sizes.
Change-Id: I1982fef776e5a0b7c613c274e544ba3e3f86f136