Fix up trivial spelling errors ('taht' -> 'that')

Pointed out by Lucas who found the new one in a comment in
setup_percpu.c. And then I fixed the others that I grepped
for.

Reported-by: Lucas <canolucas@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/video/aty/radeon_pm.c b/drivers/video/aty/radeon_pm.c
index 515cf19..c4e1764 100644
--- a/drivers/video/aty/radeon_pm.c
+++ b/drivers/video/aty/radeon_pm.c
@@ -2872,7 +2872,7 @@
 		}
 
 #if 0
-		/* Power down TV DAC, taht saves a significant amount of power,
+		/* Power down TV DAC, that saves a significant amount of power,
 		 * we'll have something better once we actually have some TVOut
 		 * support
 		 */