LinuxKPI: 802.11: hookup net80211 callbacks dependent on (*ampdu_action)()

If a LinuxkPI base wireless driver does not support the (*ampdu_action)()
ieee80211_ops function for offloading parts to firmware there is no
reason for us to hook into the net80211 callbacks either but simply
to let software (net80211) handle this.

Sponsored by: The FreeBSD Foundation (commit)
MFC after: 3 days