ixgbevf: fix possible divide by zero in ixgbevf_update_itr

The next call to ixgbevf_update_itr will continue to dynamically
update ITR.

Copy from commit bdbeefe8 ("ixgbe: fix possible divide by zero in
ixgbe_update_itr")
Signed-off-by: NYoung Xiao <92siuyang@gmail.com>
Tested-by: NAndrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c

@@ -1423,6 +1423,9 @@ static void ixgbevf_update_itr(struct ixgbevf_q_vector *q_vector,
 	 */
 	/* what was last interrupt timeslice? */
 	timepassed_us = q_vector->itr >> 2;
+	if (timepassed_us == 0)
+		return;
+
 	bytes_perint = bytes / timepassed_us; /* bytes/usec */
 
 	switch (itr_setting) {