MLBEDSW-3148: Refactor Operation

- op.type is now an enum instead of a string
- Removed unused operator codes
- Refactored some attributes like npu_block_type, fused_activation_function
- Refactored operator index calculation
- Refactored a number of operator sets

Change-Id: I641f65ee375794b7aec42abc0664251ae37d78e8
Signed-off-by: Louis Verhaard <louis.verhaard@arm.com>
diff --git a/ethosu/vela/architecture_features.py b/ethosu/vela/architecture_features.py
index 7391d71..3ef4d1b 100644
--- a/ethosu/vela/architecture_features.py
+++ b/ethosu/vela/architecture_features.py
@@ -574,7 +574,7 @@
         Cortex-Mx.intercept=<some float value>
         Cortex-Mx.slope=<some float value>
         """
-        section = "CpuPerformance." + op.type
+        section = "CpuPerformance." + op.type.name
         if self.vela_config is not None and section in self.vela_config:
             op_config = self.vela_config[section]
             try: