wifi: mac80211: fix mesh forwarding

Linearize packets (needed for forwarding A-MSDU subframes).

Fixes: 986e43b1

 ("wifi: mac80211: fix receiving A-MSDU frames on mesh interfaces")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20230324120924.38412-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>