[PATCH] x86: fix cpu_khz with clock=pit

Fix http://bugzilla.kernel.org/show_bug.cgi?id=5546

The cpu_khz global is not initialized and remains 0 if you boot with
clock=pit, even if the processor does have a TSC.  This may have bad
ramifications since the variable is used in various places scattered around
the kernel, though I didn't check them all to see if they can tolerate cpu_khz
= 0.  You can observe the problem by doing "cat /proc/cpuinfo"; the cpu MHz
line says 0.000.

The fix is trivial; call init_cpu_khz() from init_pit(), just as it's called
from the timers/timer_foo.c:init_foo() for other values of foo.

Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

arch/i386/kernel/timers/timer_pit.c

@@ -25,8 +25,9 @@ static int __init init_pit(char* override)
 {
  	/* check clock override */
  	if (override[0] && strncmp(override,"pit",3))
- 		printk(KERN_ERR "Warning: clock= override failed. Defaulting to PIT\n");
- 
+ 		printk(KERN_ERR "Warning: clock= override failed. Defaulting "
+				"to PIT\n");
+ 	init_cpu_khz();
 	count_p = LATCH;
 	return 0;
 }