wifi: ath12k: move txbaddr/rxbaddr into struct ath12k_dp

Those two fields are used to store the per SPT page of tx/rx descriptors send to
the firmware for cookie conversion. Right now they are in struct ath12k_spt_info
which means they are duplicated PPT page times while we only need one instance
of them. This works for now as we always use the first spt_info as a global
storage for all PPT pages.

Let's move them into struct ath12k_dp where they belong, alongside of the
spt_info array they are tied to, to avoid waisting a good bit of memory.

Tested-on: QCN9274 hw2.0 PCI CI_WLAN.WBE.1.3-03283.1-QCAHKSWPL_SILICONZ-2
Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3

Signed-off-by: Nicolas Escande <nico.escande@gmail.com>
Reviewed-by: Remi Pommarel <repk@triplefau.lt>
Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://patch.msgid.link/20240830081942.3623380-1-nico.escande@gmail.com