ath10k: add debugfs file to control firmware dbglog

Firmware dbglogs can be now enabled through fw_dbglog file. To enable all
possible log messages run:

echo 0xffffffff > /sys/kernel/debug/ieee80211/phy0/ath10k/fw_dbglog

And to put back firmare defaults use 0x0:

echo 0x0 > /sys/kernel/debug/ieee80211/phy0/ath10k/fw_dbglog

Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
diff --git a/drivers/net/wireless/ath/ath10k/core.h b/drivers/net/wireless/ath/ath10k/core.h
index 9d8fc29..3721c43 100644
--- a/drivers/net/wireless/ath/ath10k/core.h
+++ b/drivers/net/wireless/ath/ath10k/core.h
@@ -272,6 +272,8 @@
 	struct delayed_work htt_stats_dwork;
 	struct ath10k_dfs_stats dfs_stats;
 	struct ath_dfs_pool_stats dfs_pool_stats;
+
+	u32 fw_dbglog_mask;
 };
 
 enum ath10k_state {