update mochi attn proc

Author: a-r-r-o-w

src/diffusers/models/attention_processor.py

@@ -3847,7 +3847,7 @@ def apply_rotary_emb(x, freqs_cos, freqs_sin):
         # dropout
         hidden_states = attn.to_out[1](hidden_states)
 
-        if hasattr(attn, "to_add_out"):
+        if attn.context_pre_only is not None and not attn.context_pre_only:
             encoder_hidden_states = attn.to_add_out(encoder_hidden_states)
 
         return hidden_states, encoder_hidden_states