MLBEDSW-6371: Output diff caused by operator clone bug

- Modify the operator clone function to also clone resampling mode
attribute.

A previous patch changed the ifm resampling mode to be an attribute of
an operator rather than a tensor but did not modify the operator clone
function to clone the new attribute.

Signed-off-by: Rickard Bolin <rickard.bolin@arm.com>
Change-Id: I7a2f6103666a0997f657de20ad962e849976b904
diff --git a/ethosu/vela/operation.py b/ethosu/vela/operation.py
index d5b92d8..845d70b 100644
--- a/ethosu/vela/operation.py
+++ b/ethosu/vela/operation.py
@@ -555,6 +555,7 @@
         res.explicit_scaling = self.explicit_scaling
         res.low_precision_scaling = self.low_precision_scaling
         res.rescale = self.rescale
+        res.ifm_resampling_mode = self.ifm_resampling_mode
 
         return res