ath10k: Fix lockdep assertion warning in ath10k_sta_statistics

ath10k_debug_fw_stats_request just be called with conf_mutex held,
otherwise the following warning is seen when lock debugging is enabled:

WARNING: CPU: 0 PID: 793 at drivers/net/wireless/ath/ath10k/debug.c:357 ath10k_debug_fw_stats_request+0x12c/0x133 [ath10k_core]
Modules linked in: snd_hda_codec_hdmi designware_i2s snd_hda_intel snd_intel_dspcfg snd_hda_codec i2c_piix4 snd_hwdep snd_hda_core acpi_als kfifo_buf industrialio snd_soc_max98357a snd_soc_adau7002 snd_soc_acp_da7219mx98357_mach snd_soc_da7219 acp_audio_dma ccm xt_MASQUERADE fuse ath10k_pci ath10k_core lzo_rle ath lzo_compress mac80211 zram cfg80211 r8152 mii joydev
CPU: 0 PID: 793 Comm: wpa_supplicant Tainted: G        W         5.10.9 #5
Hardware name: HP Grunt/Grunt, BIOS Google_Grunt.11031.104.0 09/05/2019
RIP: 0010:ath10k_debug_fw_stats_request+0x12c/0x133 [ath10k_core]
Code: 1e bb a1 ff ff ff 4c 89 ef 48 c7 c6 d3 31 2e c0 89 da 31 c0 e8 bd f8 ff ff 89 d8 eb 02 31 c0 5b 41 5c 41 5d 41 5e 41 5f 5d c3 <0f> 0b e9 04 ff ff ff 0f 1f 44 00 00 55 48 89 e5 41 56 53 48 89 fb
RSP: 0018:ffffb2478099f7d0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff9e432700cce0 RCX: 11c85cfd6b8e3b00
RDX: ffff9e432700cce0 RSI: ffff9e43127c5668 RDI: ffff9e4318deddf0
RBP: ffffb2478099f7f8 R08: 0000000000000002 R09: 00000003fd7068cc
R10: ffffffffc01b2749 R11: ffffffffc029efaf R12: ffff9e432700c000
R13: ffff9e43127c33e0 R14: ffffb2478099f918 R15: ffff9e43127c33e0
FS:  00007f7ea48e2740(0000) GS:ffff9e432aa00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000059aa799ddf38 CR3: 0000000118de2000 CR4: 00000000001506f0
Call Trace:
 ath10k_sta_statistics+0x4d/0x270 [ath10k_core]
 sta_set_sinfo+0x1be/0xaec [mac80211]
 ieee80211_get_station+0x58/0x76 [mac80211]
 rdev_get_station+0xf1/0x11e [cfg80211]
 nl80211_get_station+0x7f/0x146 [cfg80211]
 genl_rcv_msg+0x32e/0x35e
 ? nl80211_stop_ap+0x19/0x19 [cfg80211]
 ? nl80211_get_station+0x146/0x146 [cfg80211]
 ? genl_rcv+0x19/0x36
 ? genl_rcv+0x36/0x36
 netlink_rcv_skb+0x89/0xfb
 genl_rcv+0x28/0x36
 netlink_unicast+0x169/0x23b
 netlink_sendmsg+0x38a/0x402
 sock_sendmsg+0x72/0x76
 ____sys_sendmsg+0x153/0x1cc
 ? copy_msghdr_from_user+0x5d/0x85
 ___sys_sendmsg+0x7c/0xb5
 ? lock_acquire+0x181/0x23d
 ? syscall_trace_enter+0x15e/0x160
 ? find_held_lock+0x3d/0xb2
 ? syscall_trace_enter+0x15e/0x160
 ? sched_clock_cpu+0x15/0xc6
 __sys_sendmsg+0x62/0x9a
 do_syscall_64+0x43/0x55
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: 4913e675 ("ath10k: enable rx duration report default for wmi tlv")
Signed-off-by: Anand K Mistry <amistry@google.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210202144033.1.I9e556f9fb1110d58c31d04a8a1293995fb8bb678@changeid

drivers/net/wireless/ath/ath10k/mac.c

@@ -9219,7 +9219,9 @@ static void ath10k_sta_statistics(struct ieee80211_hw *hw,
 	if (!ath10k_peer_stats_enabled(ar))
 		return;
 
+	mutex_lock(&ar->conf_mutex);
 	ath10k_debug_fw_stats_request(ar);
+	mutex_unlock(&ar->conf_mutex);
 
 	sinfo->rx_duration = arsta->rx_duration;
 	sinfo->filled |= BIT_ULL(NL80211_STA_INFO_RX_DURATION);