fix error of peft lora when xformers enabled (#5506)

Signed-off-by: AnyISalIn <anyisalin@gmail.com>

src/diffusers/models/attention_processor.py

@@ -909,6 +909,8 @@ class XFormersAttnProcessor:
     ):
         residual = hidden_states
 
+        args = () if USE_PEFT_BACKEND else (scale,)
+
         if attn.spatial_norm is not None:
             hidden_states = attn.spatial_norm(hidden_states, temb)
 
@@ -936,15 +938,15 @@ class XFormersAttnProcessor:
         if attn.group_norm is not None:
             hidden_states = attn.group_norm(hidden_states.transpose(1, 2)).transpose(1, 2)
 
-        query = attn.to_q(hidden_states, scale=scale)
+        query = attn.to_q(hidden_states, *args)
 
         if encoder_hidden_states is None:
             encoder_hidden_states = hidden_states
         elif attn.norm_cross:
             encoder_hidden_states = attn.norm_encoder_hidden_states(encoder_hidden_states)
 
-        key = attn.to_k(encoder_hidden_states, scale=scale)
-        value = attn.to_v(encoder_hidden_states, scale=scale)
+        key = attn.to_k(encoder_hidden_states, *args)
+        value = attn.to_v(encoder_hidden_states, *args)
 
         query = attn.head_to_batch_dim(query).contiguous()
         key = attn.head_to_batch_dim(key).contiguous()
@@ -957,7 +959,7 @@ class XFormersAttnProcessor:
         hidden_states = attn.batch_to_head_dim(hidden_states)
 
         # linear proj
-        hidden_states = attn.to_out[0](hidden_states, scale=scale)
+        hidden_states = attn.to_out[0](hidden_states, *args)
         # dropout
         hidden_states = attn.to_out[1](hidden_states)