glsl: Fix "reg" allocing

based on glasm with some tweaks

src/shader_recompiler/backend/glsl/emit_context.h

@@ -45,18 +45,14 @@ public:
         code += '\n';
     }
 
-    std::string AllocVar() {
-        return fmt::format("var_{}", var_num++);
-    }
-
     std::string code;
     RegAlloc reg_alloc;
     const Info& info;
     const Profile& profile;
-    u64 var_num{};
 
 private:
     void DefineConstantBuffers();
+    void DefineStorageBuffers();
 };
 
 } // namespace Shader::Backend::GLSL