Kernel: Remove g_program_id

This has been obsoleted by the field in Process.

src/core/loader/ncch.cpp

@@ -293,8 +293,4 @@ ResultStatus AppLoader_NCCH::ReadRomFS(std::vector<u8>& buffer) const {
     return ResultStatus::ErrorNotUsed;
 }
 
-u64 AppLoader_NCCH::GetProgramId() const {
-    return *reinterpret_cast<u64 const*>(&ncch_header.program_id[0]);
-}
-
 } // namespace Loader