Move sleep and workqueue module doc to README

sleep was broken because the workqueue was declared locally inside init,
further evidence that no one has ever run the examples :-(

kernel_module/sleep.c

@@ -1,48 +1,24 @@
-/*
-Usage:
-
-	insmod /sleep.ko
-	rmmod sleep
-
-dmesg prints an integer every second until rmmod.
-
-Since insmod returns, this also illustrates how the work queues are asynchronous.
-*/
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#sleep */
 
 #include <linux/delay.h> /* usleep_range */
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/types.h> /* atomic_t */
-#include <linux/workqueue.h>
 
-static struct workqueue_struct *queue;
-static atomic_t run = ATOMIC_INIT(1);
-
-static void work_func(struct work_struct *work)
-{
-	int i = 0;
-	while (atomic_read(&run)) {
-		pr_info("%d\n", i);
-		usleep_range(1000000, 1000001);
-		i++;
-		if (i == 10)
-			i = 0;
-	}
-}
+static u32 n = 5;
+module_param(n, int, S_IRUSR | S_IWUSR);
 
 static int myinit(void)
 {
-	DECLARE_WORK(work, work_func);
-	queue = create_workqueue("myworkqueue");
-	queue_work(queue, &work);
+	u32 i;
+	for (i = 0; i < n; ++i) {
+		pr_info("%d\n", i);
+		usleep_range(1000000, 1000001);
+	}
 	return 0;
 }
 
-static void myexit(void)
-{
-	atomic_set(&run, 0);
-	destroy_workqueue(queue);
-}
+static void myexit(void) {}
 
 module_init(myinit)
 module_exit(myexit)