Broken ARP broadcast on master (commit 0f688797)

[David Bauer]

Hi Felix,

updating my Wireless APs (ath9k+ath10k / mt7603+mt7915) broke ARP broadcast delivery to clients
connected to the radios with SW rate control.

Bisecting this problem revealed commit 0f688797 ("mac80211: add missing change for encap offload
on devices with sw rate control") introduces this problem, reverting it restored the desired
functionality.

Can you have a look what is going wrong here?

Best
David