Assign strides from iface

To simplify later checks and operations, go ahead and assign `strides`.

ucp/_libs/utils.pyx

@@ -70,8 +70,9 @@ def get_buffer_nbytes(buffer, check_min_size, cuda_support):
         shape = [int(s) for s in iface["shape"]]
         nbytes = reduce(operator.mul, shape, 1) * itemsize
         # Check that data is contiguous
-        if len(shape) > 0 and iface.get("strides") is not None:
-            strides = [int(s) for s in iface['strides']]
+        strides = iface.get("strides")
+        if len(shape) > 0 and strides is not None:
+            strides = [int(s) for s in strides]
             if len(strides) != len(shape):
                 msg = "The length of shape and strides must be equal"
                 raise ValueError(msg)