wifi: cfg80211: move A-MSDU check in ieee80211_data_to_8023_exthdr

When parsing the outer A-MSDU header, don't check for inner bridge tunnel
or RFC1042 headers. This is handled by ieee80211_amsdu_to_8023s already.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20230213100855.34315-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>