perf build: Add mypy build tests

If MYPY=1 is passed to the build then run mypy over python code in
perf. Unlike shellcheck this isn't default on as there are currently
too many errors.

An example of an error:
```
util/setup.py:8: error: Item "None" of "str | None" has no attribute "split"  [union-attr]
util/setup.py:15: error: Item "None" of "IO[bytes] | None" has no attribute "readline"  [union-attr]
util/setup.py:15: error: List item 0 has incompatible type "str | None"; expected "str | bytes | PathLike[str] | PathLike[bytes]"  [list-item]
util/setup.py:16: error: Unsupported left operand type for + ("None")  [operator]
util/setup.py:16: note: Left operand is of type "str | None"
util/setup.py:74: error: Unsupported left operand type for + ("None")  [operator]
util/setup.py:74: note: Left operand is of type "str | None"
Found 5 errors in 1 file (checked 1 source file)
make[4]: *** [util/Build:430: util/setup.py.mypy_log] Error 1
```

Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250311213628.569562-4-irogers@google.com


Signed-off-by: Namhyung Kim <namhyung@kernel.org>