/net/core/: fix misspellings using codespell tool

A typo is found out by codespell tool in 1734th line of drop_monitor.c:

$ codespell ./net/core/
./net/core/drop_monitor.c:1734: guarnateed  ==> guaranteed

Fix a typo found by codespell.
Signed-off-by: NXiong Zhenwu <xiong.zhenwu@zte.com.cn>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/drop_monitor.c

@@ -1731,7 +1731,7 @@ static void exit_net_drop_monitor(void)
 
 	/*
 	 * Because of the module_get/put we do in the trace state change path
-	 * we are guarnateed not to have any current users when we get here
+	 * we are guaranteed not to have any current users when we get here
 	 */
 
 	for_each_possible_cpu(cpu) {