MLBEDSW-3219: Suppress CPU info Const/Placeholder

Suppress info print that Const/Placeholder/SubgraphInput are not supported
on the NPU.

Change-Id: I6f323b64185b01b619b584c1473ae61d010ab3a4
Signed-off-by: Louis Verhaard <louis.verhaard@arm.com>
diff --git a/ethosu/vela/supported_operators.py b/ethosu/vela/supported_operators.py
index 4e98912..66c74fc 100644
--- a/ethosu/vela/supported_operators.py
+++ b/ethosu/vela/supported_operators.py
@@ -137,7 +137,8 @@
 
     def is_operator_supported(self, op):
         if op.type not in SupportedOperators.supported_operators:
-            print('Info: "{}" is not supported on the NPU. Placing on CPU instead'.format(op.type))
+            if op.type not in (Op.Placeholder, Op.SubgraphInput, Op.Const):
+                print("Info: {} '{}' is not supported on the NPU. Placing on CPU instead".format(op.type, op.name))
             return False
         for constraint in self.generic_constraints:
             valid, extra = constraint(op)