[PATCH 1/2][MIPS] replace c0_compare acknowledge by c0_timer_ack()

[Yoichi Yuasa <yoichi_yuasa@xxxxxxxxxxxxxx>]

VR41xx, CP0 hazard is necessary between read_c0_count() and write_c0_compare().
However, the problem can be solved by replacing this by c0_timer_ack(). 

Signed-off-by: Yoichi Yuasa <yoichi_yuasa@xxxxxxxxxxxxxx>

diff -pruN -X /home/yuasa/Memo/dontdiff linux-orig/arch/mips/kernel/cevt-r4k.c linux/arch/mips/kernel/cevt-r4k.c
--- linux-orig/arch/mips/kernel/cevt-r4k.c	2008-03-11 10:10:09.453835304 +0900
+++ linux/arch/mips/kernel/cevt-r4k.c	2008-03-12 16:35:42.911447048 +0900
@@ -186,7 +186,7 @@ static int c0_compare_int_usable(void)
 	 * IP7 already pending?  Try to clear it by acking the timer.
 	 */
 	if (c0_compare_int_pending()) {
-		write_c0_compare(read_c0_count());
+		c0_timer_ack();
 		irq_disable_hazard();
 		if (c0_compare_int_pending())
 			return 0;
@@ -198,7 +198,7 @@ static int c0_compare_int_usable(void)
 		write_c0_compare(cnt);
 		irq_disable_hazard();
 		if ((int)(read_c0_count() - cnt) < 0)
-		    break;
+			break;
 		/* increase delta if the timer was already expired */
 	}
 
@@ -208,7 +208,7 @@ static int c0_compare_int_usable(void)
 	if (!c0_compare_int_pending())
 		return 0;
 
-	write_c0_compare(read_c0_count());
+	c0_timer_ack();
 	irq_disable_hazard();
 	if (c0_compare_int_pending())
 		return 0;