wifi: ath12k: Add support RX PDEV stats

wifi: ath12k: Add support RX PDEV stats

Add support to request and receive RX pdev firmware stats using HTT
stats type 2. This stats type reports PPDU and MPDU counters, firmware
ring and buffer statistics, and RX suspend and resume counts.

Note: Currently, firmware on mobile-centric chipsets do not maintain
      these statistics, so a query will not return any information.

Sample output:
-------------
echo 2 >/sys/kernel/debug/ath12k/pci-0000\:58\:00.0/mac0/htt_stats_type
cat /sys/kernel/debug/ath12k/pci-0000\:58\:00.0/mac0/htt_stats

HTT_RX_PDEV_FW_STATS_TLV:
mac_id = 0
ppdu_recvd = 1522
mpdu_cnt_fcs_ok = 1522
mpdu_cnt_fcs_err = 0
...
fw_ring_mpdu_ind = 1522
fw_ring_mgmt_subtype =  0:0, 1:0, 2:0, 3:0, 4:21, 5:0, 6:0, 7:0, 8:1501, 9:0, 10:0, 11:0, 12:0, 13:0, 14:0, 15:0
fw_ring_ctrl_subtype =  0:0, 1:0, 2:0, 3:0, 4:0, 5:0, 6:0, 7:0, 8:0, 9:0, 10:0, 11:0, 12:0, 13:0, 14:0, 15:0
fw_ring_mcast_data_msdu = 0
fw_pkt_buf_ring_refill_cnt = 1567
fw_pkt_buf_ring_empty_cnt = 1
...
rx_suspend_cnt = 4
rx_suspend_fail_cnt = 0
rx_resume_cnt = 4
rx_resume_fail_cnt = 0
rx_ring_switch_cnt = 0
rx_ring_restore_cnt = 0

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.5-01651-QCAHKSWPL_SILICONZ-1

Signed-off-by: Aaradhana Sahu <aaradhana.sahu@oss.qualcomm.com>
Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Link: https://patch.msgid.link/20260123071253.2202644-3-aaradhana.sahu@oss.qualcomm.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>