e1000: drop unneeded assignment in e1000_set_itr()

The variable 'current_itr' is assigned to 0 before jumping to
'set_itr_now' but it has not been used after the jump. So, remove the
unneeded assignment.
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Reviewed-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/e1000/e1000_main.c

@@ -2632,7 +2632,6 @@ static void e1000_set_itr(struct e1000_adapter *adapter)
 
 	/* for non-gigabit speeds, just fix the interrupt rate at 4000 */
 	if (unlikely(adapter->link_speed != SPEED_1000)) {
-		current_itr = 0;
 		new_itr = 4000;
 		goto set_itr_now;
 	}