[NPUW] Fix serialization (#31496)

Bug introduced here
#31294

Author: smirnov-alexey

src/plugins/intel_npu/src/plugin/npuw/llm_compiled_model.cpp

@@ -1284,6 +1284,7 @@ void ov::npuw::LLMCompiledModel::serialize(std::ostream& stream, const ov::npuw:
         write(model_stream, m_kvcache_desc.num_stored_tokens);
         write(model_stream, m_kvcache_desc.dim);
         write(model_stream, m_kvcache_desc.v_tensors_transposed);
+        write(model_stream, m_prefill_chunk_size);
 
         // Write config
         write(model_stream, m_cfg);
@@ -1474,6 +1475,7 @@ std::shared_ptr<ov::npuw::LLMCompiledModel> ov::npuw::LLMCompiledModel::deserial
         read(model_stream, compiled->m_kvcache_desc.num_stored_tokens);
         read(model_stream, compiled->m_kvcache_desc.dim);
         read(model_stream, compiled->m_kvcache_desc.v_tensors_transposed);
+        read(model_stream, compiled->m_prefill_chunk_size);
 
         // Deserialize config
         read(model_stream, compiled->m_cfg);

src/plugins/intel_npu/src/plugin/npuw/llm_compiled_model.hpp

@@ -68,7 +68,7 @@ class LLMCompiledModel : public ov::npuw::ICompiledModel {
     ov::npuw::s11n::BF16Cache m_bf16_consts;
 
     KVCacheDesc m_kvcache_desc;
-    uint64_t m_prefill_chunk_size;
+    uint64_t m_prefill_chunk_size = 0;
     std::shared_ptr<ov::npuw::CompiledModel> m_kvcache_compiled;
     std::shared_ptr<ov::npuw::CompiledModel> m_prefill_compiled;
     // This model is optional, so can be null.

src/plugins/intel_npu/src/plugin/npuw/serialization.hpp

@@ -34,7 +34,7 @@ const constexpr ov::npuw::s11n::IndicatorType NPUW_COMPILED_MODEL_INDICATOR =
 const constexpr ov::npuw::s11n::IndicatorType NPUW_LLM_COMPILED_MODEL_INDICATOR =
     {char{0x4c}, char{0x4c}, char{0x4d}, char{0x43}, char{0x4d}, char{0x4f}};
 
-const constexpr char* NPUW_SERIALIZATION_VERSION = "0.5";
+const constexpr char* NPUW_SERIALIZATION_VERSION = "0.6";
 
 // Forward declaration
 namespace intel_npu {