[POWERPC] Convert therm_pm72.c to use the kthread API

This converts the therm_pm72.c driver to use the kthread API.  I
thought about making it use kthread_stop() instead of the `state'
variable and the `ctrl_complete' completion, but that isn't simple and
will require changing the way that `state' is used.
Signed-off-by: Paul Mackerras <paulus@samba.org>

drivers/macintosh/therm_pm72.c

@@ -121,6 +121,7 @@
 #include <linux/reboot.h>
 #include <linux/kmod.h>
 #include <linux/i2c.h>
+#include <linux/kthread.h>
 #include <asm/prom.h>
 #include <asm/machdep.h>
 #include <asm/io.h>
@@ -161,7 +162,7 @@ static struct slots_pid_state		slots_state;
 static int				state;
 static int				cpu_count;
 static int				cpu_pid_type;
-static pid_t				ctrl_task;
+static struct task_struct		*ctrl_task;
 static struct completion		ctrl_complete;
 static int				critical_state;
 static int				rackmac;
@@ -1779,8 +1780,6 @@ static int call_critical_overtemp(void)
  */
 static int main_control_loop(void *x)
 {
-	daemonize("kfand");
-
 	DBG("main_control_loop started\n");
 
 	down(&driver_lock);
@@ -1956,7 +1955,7 @@ static void start_control_loops(void)
 {
 	init_completion(&ctrl_complete);
 
-	ctrl_task = kernel_thread(main_control_loop, NULL, SIGCHLD | CLONE_KERNEL);
+	ctrl_task = kthread_run(main_control_loop, NULL, "kfand");
 }
 
 /*
@@ -1964,7 +1963,7 @@ static void start_control_loops(void)
  */
 static void stop_control_loops(void)
 {
-	if (ctrl_task != 0)
+	if (ctrl_task)
 		wait_for_completion(&ctrl_complete);
 }