use the new devices.has_mps() function in register_buffer for DDIM/PLMS fix for OSX

modules/sd_hijack.py

@@ -418,8 +418,7 @@ def register_buffer(self, name, attr):
     if type(attr) == torch.Tensor:
         if attr.device != devices.device:
 
-            # would this not break cuda when torch adds has_mps() to main version?
-            if getattr(torch, 'has_mps', False):
+            if devices.has_mps():
                 attr = attr.to(device="mps", dtype=torch.float32)
             else:
                 attr = attr.to(devices.device)