[device-data] Replace bash HwSKU loop with Python for ~200x speedup

[rustiqly]

What I did

Replaced the ~100-line bash while-read loop in src/sonic-device-data/Makefile with a Python script (generate_vs_hwsku.py) that generates VS HwSKU data ~200x faster.

Why I did it

The sonic-device-data package build generates VS HwSKU mappings (lanemap.ini, coreportindexmap.ini, SAI profiles) for all ~470 hardware SKUs. The existing bash implementation uses a while IFS= read -r line loop with per-line awk calls and grep pattern matching. On a 24-core build machine, this takes ~9 minutes — significant when the full VS build is ~50 minutes.

The Python replacement processes all 477 HwSKUs in <1 second.

How I did it

• Added src/sonic-device-data/src/generate_vs_hwsku.py — handles all cases: chassis configs with midplane reservation, multi-ASIC subdirectories (0/1/2), profile copying, context_config.json cleanup
• Simplified the Makefile to call the Python script instead of the inline bash loop
• The rest of the Makefile (device copy, mellanox simx SAI_KEY_IS_SIMX, dpkg-buildpackage) is unchanged

Bugfix included

The bash loop had a minor bug: empty lines in port_config.ini (common in files with license headers) were not skipped by the grep -q "^#" check, creating lanemap entries like eth1: with empty lanes. The Python version correctly skips blank lines, fixing 30 HwSKUs.

How to verify it

# Time comparison (run inside sonic-slave container):
cd src/sonic-device-data/src
rm -rf device && mkdir device && cp -r -L ../../../device/*/* device/

# Python (new):
time python3 ./generate_vs_hwsku.py ../../../device
# Result: ~0.6 seconds

# Verify output:
ls device/x86_64-kvm_x86_64-r0/ | wc -l  # Should be ~477
cat device/x86_64-kvm_x86_64-r0/Force10-S6000/lanemap.ini  # 32 ports

[mssonicbld]

/azp run Azure.sonic-buildimage

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[lihuay]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).