opengnb: add opengnb 1.6.8 to openwrt - #29879

Checking PR #29879: opengnb: add opengnb 1.6.8 to openwrt (Formalities Audit)

✅ Pull request originates from a dedicated feature branch (opengnb-1.6.5)

Commit 0bac353 - opengnb: add version 1.6.8:

✅ Author and committer identities are valid
✅ Commit is not a merge commit
✅ Commit subject layout and length are valid: "opengnb: add version 1.6.8"
✅ Commit description lines adhere to width formatting rules
✅ Commit contains a valid 'Signed-off-by:' line matching author or committer
✅ Excellent! Commit contains a valid cryptographic signature (GPG/SSH). Thank you for signing your work! (SSH Key Fingerprint: SHA256:Ctocwxxn3Z+qDKPcDaHDgGAQlke4mqe5HODFXY2QVRc)
⚠️ Warning: No reference link (e.g., upstream release notes, changelog, or history URL) detected in description.