fix(DDIM scheduler): use correct dtype for noise (#742)

Otherwise, it crashes when eta > 0 with float16.

src/diffusers/schedulers/scheduling_ddim.py

@@ -283,8 +283,9 @@ class DDIMScheduler(SchedulerMixin, ConfigMixin):
         prev_sample = alpha_prod_t_prev ** (0.5) * pred_original_sample + pred_sample_direction
 
         if eta > 0:
+            # randn_like does not support generator https://github.com/pytorch/pytorch/issues/27072
             device = model_output.device if torch.is_tensor(model_output) else "cpu"
-            noise = torch.randn(model_output.shape, generator=generator).to(device)
+            noise = torch.randn(model_output.shape, dtype=model_output.dtype, generator=generator).to(device)
             variance = self._get_variance(timestep, prev_timestep) ** (0.5) * eta * noise
 
             prev_sample = prev_sample + variance