net: Mac80211: Remove silly timespec dance

Converting time from one format to another seems to give coders a warm
and fuzzy feeling.

Use the proper interfaces.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John W. Linville <linville@tuxdriver.com>
[fix compile error]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index ba29ebc..aa06dca 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -473,8 +473,6 @@
 					    struct sta_info *sta,
 					    struct ieee80211_hdr *hdr)
 {
-	ktime_t skb_dprt;
-	struct timespec dprt_time;
 	u32 msrmnt;
 	u16 tid;
 	u8 *qc;
@@ -506,9 +504,8 @@
 
 	tx_lat = &sta->tx_lat[tid];
 
-	ktime_get_ts(&dprt_time); /* time stamp completion time */
-	skb_dprt = ktime_set(dprt_time.tv_sec, dprt_time.tv_nsec);
-	msrmnt = ktime_to_ms(ktime_sub(skb_dprt, skb_arv));
+	/* Calculate the latency */
+	msrmnt = ktime_to_ms(ktime_sub(ktime_get(), skb_arv));
 
 	if (tx_lat->max < msrmnt) /* update stats */
 		tx_lat->max = msrmnt;