[TCP]: Fix linkage errors on i386.

To avoid raw division, use ktime_to_timeval() to get usec.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/ktime.h b/include/linux/ktime.h
index 248305b..81bb9c7 100644
--- a/include/linux/ktime.h
+++ b/include/linux/ktime.h
@@ -259,6 +259,12 @@
 
 #endif
 
+static inline s64 ktime_to_us(const ktime_t kt)
+{
+	struct timeval tv = ktime_to_timeval(kt);
+	return (s64) tv.tv_sec * USEC_PER_SEC + tv.tv_usec;
+}
+
 /*
  * The resolution of the clocks. The resolution value is returned in
  * the clock_getres() system call to give application programmers an