wifi: ath12k: Handle DP_RX_DECAP_TYPE_8023 type in Rx path

wifi: ath12k: Handle DP_RX_DECAP_TYPE_8023 type in Rx path

The driver does not currently set any rx_flag for frames received with
decap type DP_RX_DECAP_TYPE_8023. When the hardware reports
LLC-encapsulated packets whose length field is below 0x0600, the MSDU_END
descriptor may indicate decap type DP_RX_DECAP_TYPE_8023.

These frames are effectively equivalent to Ethernet-II (DIX) packets,
similar to those decoded as DP_RX_DECAP_TYPE_ETHERNET2_DIX. If the
driver does not set RX_FLAG_8023 for these frames, mac80211 will
misinterpret them as 802.11 frames. This causes valid frames such as
Bridge Protocol Data Units (BPDUs) to be dropped. BPDUs are exchanged
between switches to maintain and manage network topology, and must
be treated as Ethernet frames.

Set RX_FLAG_8023 for decap type DP_RX_DECAP_TYPE_8023 in
ath12k_dp_rx_h_undecap() to ensure mac80211 handles these frames
correctly. Also add multicast packet handling support for the
DP_RX_DECAP_TYPE_8023 decap type.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.6-01243-QCAHKSWPL_SILICONZ-1

Signed-off-by: Tamizh Chelvam Raja <tamizh.raja@oss.qualcomm.com>
Reviewed-by: Rameshkumar Sundaram <rameshkumar.sundaram@oss.qualcomm.com>
Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Link: https://patch.msgid.link/20260418163620.3633959-1-tamizh.raja@oss.qualcomm.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>