wifi: ath12k: Enable Ethernet encapsulation hardware offload

Introduce a module parameter for runtime frame mode configuration and
set the default mode to Ethernet encapsulation offload and advertise
Ethernet encapsulation hardware offload support to mac80211.

Signed-off-by: Nithyanantham Paramasivam <quic_nithp@quicinc.com>
Signed-off-by: Raj Kumar Bhagat <quic_rajkbhag@quicinc.com>
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>