Wire target_config Buck deps on cmsis_nn_py (pytorch#19604) (pytorch#19604)

Summary:

A previous change added `executorch/backends/cortex_m/target_config.py`
(and `passes/cortex_m_pass.py`) but did not wire them into the cortex_m
Buck graph. As a result, importing
`executorch.backends.cortex_m.passes.cortex_m_pass_manager` from any
consumer fails at import time with:

```
ModuleNotFoundError: No module named 'executorch.backends.cortex_m.target_config'
```

This change wires the new files into Buck and connects them to the
newly-buckified `cmsis_nn` Python package:

- New `//executorch/backends/cortex_m:target_config` `python_library`
exporting `target_config.py`, depending on
`//third-party/cmsis-nn:cmsis_nn_py` (added earlier in this stack).
- `//executorch/backends/cortex_m/passes:cortex_passes`: add
`cortex_m_pass.py` to `srcs` (needed because `passes/__init__.py` does
`from .cortex_m_pass import CortexMPass`), and add `:target_config` to
`deps` so `cortex_m_pass_manager.py` and `cortex_m_pass.py` can resolve
their `target_config` import.

Reviewed By: psiddh

Differential Revision: D105210239

Author: rascani

backends/cortex_m/TARGETS

@@ -19,3 +19,13 @@ python_library(
         "fbsource//third-party/pypi/tabulate:tabulate",
     ],
 )
+
+python_library(
+    name = "target_config",
+    srcs = [
+        "target_config.py",
+    ],
+    deps = [
+        "fbsource//third-party/cmsis-nn:cmsis_nn_py",
+    ],
+)

backends/cortex_m/passes/BUCK

@@ -31,6 +31,7 @@ fbcode_target(_kind = runtime.python_library,
         "activation_fusion_pass.py",
         "clamp_hardswish_pass.py",
         "convert_to_cortex_m_pass.py",
+        "cortex_m_pass.py",
         "cortex_m_pass_manager.py",
         "decompose_hardswish_pass.py",
         "decompose_mean_pass.py",
@@ -39,6 +40,7 @@ fbcode_target(_kind = runtime.python_library,
     deps=[
         "//caffe2:torch",
         "//executorch/backends/arm/_passes:passes",
+        "//executorch/backends/cortex_m:target_config",
         "//executorch/backends/cortex_m/ops:ops",
         "//executorch/backends/cortex_m/passes:passes_utils",
         "//executorch/backends/cortex_m/passes:replace_quant_nodes_pass",