Qualcomm AI Engine Direct - Fix HF Qwen (pytorch#20317)

### Summary
Mainline HF Qwen is broken.
This needs to be resolved in order to enable HF LLM flow in Optimum
ExecuTorch

### Test plan
Passings e2e test in test_qnn_delegate.py

Author: winskuo-quic

examples/qualcomm/oss_scripts/llm_utils/decoder_model_wrapper.py

@@ -38,7 +38,10 @@ def save_config_to_constant_methods(
         # Check for cache_config and its attributes
         cache_config = getattr(generation_config, "cache_config", None)
         if cache_config is not None:
-            max_seq_len = getattr(cache_config, "max_cache_len", None)
+            if isinstance(cache_config, dict):
+                max_seq_len = cache_config.get("max_cache_len", None)
+            else:
+                max_seq_len = getattr(cache_config, "max_cache_len", None)
             if max_seq_len is not None:
                 metadata["get_max_seq_len"] = max_seq_len
 
@@ -115,7 +118,7 @@ def _qnn_attention_mask(
 
     # Simplest and most efficient way to obtain a causal mask
     causal_mask = kv_arange <= reshaped_cache_position
-    atten_mask = torch.full((causal_mask.shape[0], kv_length), torch.tensor(-65504.0))
+    atten_mask = torch.full((causal_mask.shape[0], kv_length), -65504.0)
     atten_mask = atten_mask.masked_fill(causal_mask, 0)
     atten_mask = atten_mask[None, None, :, :].expand(batch_size, -1, -1, -1)
 
@@ -133,7 +136,7 @@ def __init__(self, model):
         logging.info(f"Metadata to be recorded in PTE: {self._metadata}")
         self.exportable_module = TorchExportableModuleForDecoderOnlyLM(
             self.model,
-            max_batch_size=1,
+            batch_size=1,
             max_cache_len=self._metadata.get("get_max_seq_len"),
         )
         self._register_attention_mask_for_4_53(self.exportable_module)
@@ -154,7 +157,9 @@ def get_example_inputs(self):
         return (example_input_ids, example_cache_position)
 
     def forward(self, input_ids: torch.Tensor, cache_position: torch.Tensor):
-        return self.exportable_module(input_ids, cache_position)
+        return self.exportable_module(
+            input_ids=input_ids, cache_position=cache_position
+        )
 
     def get_metadata(self):
         return self._metadata

examples/qualcomm/oss_scripts/qwen2_5/qwen2_5.py

@@ -14,7 +14,6 @@
 
 import torch
 from executorch.backends.qualcomm.export_utils import (
-    get_backend_type,
     QnnConfig,
     setup_common_args_and_variables,
     SimpleADB,
@@ -75,7 +74,7 @@ def compile(args: argparse.Namespace, qnn_config: QnnConfig):  # noqa: C901
             args.calibration_limit,
             args.prompt,
             tokenizer_json_path,
-            get_backend_type(qnn_config.backend),
+            qnn_config.backend,
             qnn_config.soc_model,
         )
 
@@ -158,7 +157,7 @@ def post_process():
             runner="examples/models/llama/llama_main",
         )
         # No pregen inputs, input_list is not required
-        adb.push(inputs=[], input_list="", files=[tokenizer_json_path])
+        adb.push(inputs=[], files=[tokenizer_json_path])
         adb.execute(custom_runner_cmd=runner_cmd)
 
         adb.pull(host_output_path=args.artifact, callback=post_process)