[MIPS] AU1xxx mips_timer_interrupt() fixes
    
common/au1000/irq.c was missing a mips_timer_interrupt() prototype,
whereas in common/au1000/time.c the actual mips_timer_interrupt()
implementation was missing an irq_exit() invocation, causing a
preempt_count() leak.
    
Signed-off-by: Herbert Valerio Riedel <hvr@hvrlab.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/au1000/common/time.c b/arch/mips/au1000/common/time.c
index f85f152..f74d66a 100644
--- a/arch/mips/au1000/common/time.c
+++ b/arch/mips/au1000/common/time.c
@@ -116,6 +116,7 @@
 
 null:
 	ack_r4ktimer(0);
+	irq_exit();
 }
 
 #ifdef CONFIG_PM