fix enable memory efficient attention on ROCm

while calling CK implementation

Author: tenpercent

src/diffusers/models/attention_processor.py

@@ -399,11 +399,8 @@ def set_use_memory_efficient_attention_xformers(
             else:
                 try:
                     # Make sure we can run the memory efficient attention
-                    _ = xformers.ops.memory_efficient_attention(
-                        torch.randn((1, 2, 40), device="cuda"),
-                        torch.randn((1, 2, 40), device="cuda"),
-                        torch.randn((1, 2, 40), device="cuda"),
-                    )
+                    q = torch.randn((1, 2, 40), device="cuda", dtype=torch.float16)
+                    _ = xformers.ops.memory_efficient_attention(q, q, q)
                 except Exception as e:
                     raise e