wifi: iwlwifi: mvm: mark mac header with no data frames

Although no data is presented in the skb, but upper layers need it for
calculating where radio tap header are done, so we mark it.

Signed-off-by: Mordechay Goodstein <mordechay.goodstein@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230305124406.8f53cc8579bf.I8819c005b4953cea03346d0aff82b31d94f79fe5@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>