[MIPS] time: Make c0_compare_int_usable more bullet proof

Use write_c0_compare(read_c0_count()) to clear interrupt.
Signed-off-by: NAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/kernel/cevt-r4k.c

@@ -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_compare());
+		write_c0_compare(read_c0_count());
 		irq_disable_hazard();
 		if (c0_compare_int_pending())
 			return 0;
@@ -202,7 +202,7 @@ static int c0_compare_int_usable(void)
 	if (!c0_compare_int_pending())
 		return 0;
 
-	write_c0_compare(read_c0_compare());
+	write_c0_compare(read_c0_count());
 	irq_disable_hazard();
 	if (c0_compare_int_pending())
 		return 0;