comment out unused import for cp

Signed-off-by: Xin Yao <xiny@nvidia.com>

Author: yaox12

transformer_engine/pytorch/attention/dot_product_attention/backends.py

@@ -162,15 +162,16 @@
 except PackageNotFoundError:
     flash_attn_func_v4 = None
     flash_attn_varlen_func_v4 = None
-    # flash_attn_combine_v4 = None
-    _flash_attn_fwd_v4 = None
-    _flash_attn_bwd_v4 = None
+    # TODO: for context parallel
+    # _flash_attn_fwd_v4 = None
+    # _flash_attn_bwd_v4 = None
 else:
-    from flash_attn.cute.interface import (  # pylint: disable=ungrouped-imports
+    from flash_attn.cute.interface import (  # pylint: disable=ungrouped-imports,no-name-in-module
         flash_attn_func as flash_attn_func_v4,
         flash_attn_varlen_func as flash_attn_varlen_func_v4,
-        _flash_attn_fwd as _flash_attn_fwd_v4,
-        _flash_attn_bwd as _flash_attn_bwd_v4,
+        # TODO: for context parallel
+        # _flash_attn_fwd as _flash_attn_fwd_v4,
+        # _flash_attn_bwd as _flash_attn_bwd_v4,
     )
 
     fa_utils.set_flash_attention_4_params()