mitigate qualcomm build issue

Author: Gasoonjia

extension/llm/tokenizers

@@ -465,13 +465,11 @@ def run(self):
 
         try:
             # Following code is for building the Qualcomm backend.
-            from backends.qualcomm.scripts.download_qnn_sdk import (
-                _download_qnn_sdk,
-                is_linux_x86,
-            )
+            from backends.qualcomm.scripts.download_qnn_sdk import is_linux_x86
 
             if is_linux_x86():
                 os.environ["EXECUTORCH_BUILDING_WHEEL"] = "1"
+                from backends.qualcomm.scripts.download_qnn_sdk import _download_qnn_sdk
 
                 with tempfile.TemporaryDirectory() as tmpdir:
                     tmp_path = Path(tmpdir)
@@ -537,8 +535,8 @@ def run(self):
                         self.copy_file(str(so_src), str(so_dst))
                         logging.info(f"Copied Qualcomm backend: {so_src} -> {so_dst}")
 
-        except ImportError:
-            logging.error("Fail to build Qualcomm backend")
+        except ImportError as e:
+            logging.error(f"Fail to build Qualcomm backend: {e}")
             logging.exception("Import error")
 
         if self.editable_mode: