ath11k: fix read fail for htt_stats and htt_peer_stats for single pdev

ath11k: fix read fail for htt_stats and htt_peer_stats for single pdev

The pdev id is set to 0 for single pdev configured hardware, the real
pdev id is not 0 in firmware, for example, its pdev id is 1 for 5G/6G
phy and 2 for 2G band phy. For HTT_H2T_MSG_TYPE_EXT_STATS_CFG message,
firmware parse the pdev_mask to its pdev id, ath11k set it to 0 for
single pdev, it is not correct, need set it with the real pdev id of
firmware.

Save the real pdev id report by firmware and set it correctly.

Below commands run success with this patch:
cat /sys/kernel/debug/ieee80211/phy0/ath11k/htt_stats
cat /sys/kernel/debug/ieee80211/phy0/netdev\:wls1/stations/00\:03\:7f\:75\:59\:85/htt_peer_stats

Tested-on: QCA6390 hw2.0 PCI WLAN.HST.1.0.1-01740-QCAHSTSWPLZ_V2_TO_X86-1

Signed-off-by: Wen Gong <quic_wgong@quicinc.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20211118095700.8149-1-quic_wgong@quicinc.com