MLBEDSW-4856: Removed dead code

Hardswish activation function gets converted to LUT in graph optimizer. The case for it was removed, as it was never called. 


Signed-off-by: oliper01 <oliver.perssonbogdanovski@arm.com>
Change-Id: I376e8d7b81489c06b66d4e49f59b207600c0ccce
diff --git a/ethosu/vela/operation.py b/ethosu/vela/operation.py
index 6b6671b..9488fb7 100644
--- a/ethosu/vela/operation.py
+++ b/ethosu/vela/operation.py
@@ -436,9 +436,7 @@
     elif op_type == Op.Sigmoid:
         act.min = 0.0
         act.max = 1.0
-    elif op_type == Op.HardSwish:
-        act.min = 0.0
-    if op_type == Op.Clamp:
+    elif op_type == Op.Clamp:
         assert min is not None and max is not None
         act.min = min
         act.max = max