SchSeba / ib-sriov-cni / 21545935772

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Fix "message too long" error for InfiniBand devices with many VFs

When configuring InfiniBand devices with many VFs, LinkByName() can fail
with "message too long" (EMSGSIZE) because the kernel's netlink response
exceeds the message limit. This happens because LinkByName requests all
VF info (including GUIDs) which generates very large messages for IB
devices.

This commit adds a fallback mechanism:
- Add LinkByNameForSetVf() method that reads minimal link info (name and
  index) directly from sysfs instead of using netlink
- Update ApplyVFConfig() and ResetVFConfig() to catch EMSGSIZE errors
  and fall back to LinkByNameForSetVf()
- Add path traversal protection for interface names

The fallback only triggers when the specific EMSGSIZE error occurs,
preserving normal behavior for devices with fewer VFs.

Signed-off-by: User <user@example.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

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