wil6210: interrupt statistics

Track number of interrupts and Tx/Rx packets;
expose through debugfs 'info'. Reset upon read.
Used to analyse effectivness of interrupt coalescing and NAPI.
Read twice with some interval like
cat info > /dev/null; sleep 1; cat info

Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/wil6210/interrupt.c b/drivers/net/wireless/ath/wil6210/interrupt.c
index e4aba53..67f1002 100644
--- a/drivers/net/wireless/ath/wil6210/interrupt.c
+++ b/drivers/net/wireless/ath/wil6210/interrupt.c
@@ -208,6 +208,7 @@
 
 	/* Rx IRQ will be enabled when NAPI processing finished */
 
+	atomic_inc(&wil->isr_count_rx);
 	return IRQ_HANDLED;
 }
 
@@ -246,6 +247,7 @@
 
 	/* Tx IRQ will be enabled when NAPI processing finished */
 
+	atomic_inc(&wil->isr_count_tx);
 	return IRQ_HANDLED;
 }