ath10k_sta_statistics is used to report many info to iw wlan0 link,
if it return for empty legacy and nss of arsta->txrate, then the other
stats after it will not be set.

It has 4 bit to set after the return:
NL80211_STA_INFO_TX_FAILED
NL80211_STA_INFO_RX_BITRATE
NL80211_STA_INFO_TX_BITRATE
NL80211_STA_INFO_TX_RETRIES

This patch not effect the info of above 4 bit for all hardware, reason
as below:

NL80211_STA_INFO_TX_FAILED is only for htt.disable_tx_comp is true, it
is for QCA6174 SDIO.

NL80211_STA_INFO_RX_BITRATE and NL80211_STA_INFO_TX_BITRATE are both
set in ath10k_mac_sta_get_peer_stats_info, it is only enabled for chips
which supports_peer_stats_info is true in hw_params, recently only for
QCA6174 SDIO, NL80211_STA_INFO_TX_BITRATE is set again in function
ath10k_mac_sta_get_peer_stats_info because the value which parsed from
arsta->tx_rate_code and arsta->tx_bitrate_kbps is correct for QCA6174
SDIO and PCIe, and the value arsta->txrate is not correct for QCA6174
SDIO and PCIe, so it need to set again with the correct value.

NL80211_STA_INFO_TX_RETRIES is use value of arsta->tx_retries, it is set
in ath10k_update_per_peer_tx_stats, which accumulate the retry_pkts in
HTT message from firmware, if the chips not support this feature, then
it is always 0 after accumulate, then iw wlan0 station dump always show
0 for retry count. If not set NL80211_STA_INFO_TX_RETRIES here, then it
is still 0, so the result is same, then set NL80211_STA_INFO_TX_RETRIES
has no effect.

Tested-on: QCA6174 hw3.2 SDIO WLAN.RMH.4.4.1-00048
Tested-on: QCA6174 hw3.2 PCI WLAN.RM.4.4.1-00110-QCARMSWP-1
Signed-off-by: Wen Gong <wgong@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1597312029-32348-3-git-send-email-wgong@codeaurora.org