wifi: ath12k: Move ath12k_dp_tx and related APIs to wifi7 directory

wifi: ath12k: Move ath12k_dp_tx and related APIs to wifi7 directory

Move arch specific TX data path to wifi7 directory as part of Next
Generation (NG) Driver Framework.

Architecture specific APIs:
ath12k_hal_tx_cmd_ext_desc_setup
ath12k_dp_prepare_htt_metadata
ath12k_dp_tx

The moved APIs will be a part of dp_tx.c file inside wifi7 directory.
wifi7/dp_tx.c file will continue to be part of ath12k.ko temporarily
until the corresponding infra for movement to ath12k_wifi7.ko arrives
in upcoming patches.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.4.1-00199-QCAHKSWPL_SILICONZ-1
Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3

Signed-off-by: Pavankumar Nandeshwar <quic_pnandesh@quicinc.com>
Signed-off-by: Ripan Deuri <quic_rdeuri@quicinc.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Link: https://patch.msgid.link/20250828173553.3341351-17-quic_rdeuri@quicinc.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>