wifi-scripts: only enable RSN override when parameters differ

wifi-scripts: only enable RSN override when parameters differ

When encryption is set to 'sae' without explicit pairwise cipher in
non-HE/EHT mode, both the main RSNE and override RSNE would advertise
identical parameters (SAE+CCMP+MFP=2), adding unnecessary overhead.

Check that the pairwise ciphers differ before enabling override. This
preserves the intended behavior for HE/EHT modes (GCMP-256+CCMP vs CCMP)
while avoiding pointless override IEs.

Reported-by: Michael-cy Lee (李峻宇) <[email protected]>
Signed-off-by: Felix Fietkau <[email protected]>