iwlwifi: mvm: fix security bug in PN checking

A previous patch allowed the same PN for packets originating from the
same AMSDU by copying PN only for the last packet in the series.

This however is bogus since we cannot assume the last frame will be
received on the same queue, and if it is received on a different ueue
we will end up not incrementing the PN and possibly let the next
packet to have the same PN and pass through.

Change the logic instead to driver explicitly indicate for the second
sub frame and on to be allowed to have the same PN as the first
subframe. Indicate it to mac80211 as well for the fallback queue.

Fixes: f1ae02b1 ("iwlwifi: mvm: allow same PN for de-aggregated AMSDU")
Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>