MLBEDSW-3367 Add mypy to pre-commit

Add mypy to pre-commit and clean up all reported errors.

Signed-off-by: Jonas Ohlsson <jonas.ohlsson@arm.com>
Change-Id: If7dc869f5fecdb0e2db40f14e7d9db21aa33df71
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 8e976b6..ae2bae5 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,5 +1,14 @@
 exclude: '^ethosu/vela/(tflite|ethos_u55_regs|tosa)/'
 repos:
+-   repo: https://github.com/pre-commit/mirrors-mypy
+    rev: 'v0.931'
+    hooks:
+    -   id: mypy
+        args: ["--no-strict-optional", "--show-error-codes", "--ignore-missing-imports"]
+        require_serial: true
+        additional_dependencies: [types-setuptools]
+        minimum_pre_commit_version: '2.9.2'
+
 -   repo: https://github.com/asottile/reorder_python_imports
     rev: v2.2.0
     hooks: