MLBEDSW-6832 PReLU support in Vela

Added PReLU support in graph optimiser.

Signed-off-by: Fredrik Svedberg <fredrik.svedberg@arm.com>
Change-Id: I3a188675e3edcdf0b4a4bfcdd134fda0bf8a560f
diff --git a/ethosu/vela/tflite_supported_operators.py b/ethosu/vela/tflite_supported_operators.py
index 5d25e37..1915d43 100644
--- a/ethosu/vela/tflite_supported_operators.py
+++ b/ethosu/vela/tflite_supported_operators.py
@@ -123,7 +123,15 @@
             Op.Clip,
         )
     )
-    activation_ops = relu_ops | set((Op.Tanh, Op.Sigmoid, Op.Softmax, Op.HardSwish))
+    activation_ops = relu_ops | set(
+        (
+            Op.Tanh,
+            Op.Sigmoid,
+            Op.Softmax,
+            Op.HardSwish,
+            Op.Prelu,
+        )
+    )
     npu_post_ops = (
         # activation functions
         activation_ops