kv-cache : fix SWA checks + disable cacheless iSWA (#15811)

ggml-ci

src/llama-kv-cache.h

@@ -89,6 +89,7 @@ public:
                      uint32_t   n_seq_max,
                      uint32_t   n_pad,
                      uint32_t   n_swa,
+               llama_swa_type   swa_type,
         const layer_filter_cb & filter,
         const  layer_reuse_cb & reuse);
 
@@ -211,6 +212,9 @@ private:
     // env: LLAMA_KV_CACHE_DEBUG
     int debug = 0;
 
+    // this is the SWA type of the cache - not to be confused with the model SWA type
+    const llama_swa_type swa_type = LLAMA_SWA_TYPE_NONE;
+
     std::vector<ggml_context_ptr>        ctxs;
     std::vector<ggml_backend_buffer_ptr> bufs;