refactor: Extract PostSyncType to outer abstract layer

This modification serves to simplify the integration of generated
compute walker structures.

Related-To: NEO-13147

Signed-off-by: Vysochyn, Illia <illia.vysochyn@intel.com>

shared/source/xe_hpg_core/hw_cmds_xe_hpg_core_base.h

@@ -178,6 +178,12 @@ struct XeHpgCoreFamily : public XeHpgCore {
     static constexpr bool isInterfaceDescriptorHeaplessMode() {
         return false;
     }
+
+    template <typename WalkerType>
+    static auto getPostSyncType() {
+        return std::decay_t<POSTSYNC_DATA>{};
+    }
+
     using WalkerVariant = std::variant<COMPUTE_WALKER *>;
 };