aio / timers: Rename qemu_timer_* functions

Rename four functions in preparation for new API.

Rename qemu_timer_expired to timer_expired
Rename qemu_timer_expire_time_ns to timer_expire_time_ns
Rename qemu_timer_pending to timer_pending
Rename qemu_timer_expired_ns to timer_expired_ns

Signed-off-by: Alex Bligh <alex@alex.org.uk>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/hw/mips/cputimer.c b/hw/mips/cputimer.c
index e0266bf..739bbac 100644
--- a/hw/mips/cputimer.c
+++ b/hw/mips/cputimer.c
@@ -72,8 +72,8 @@
         uint64_t now;
 
         now = qemu_get_clock_ns(vm_clock);
-        if (qemu_timer_pending(env->timer)
-            && qemu_timer_expired(env->timer, now)) {
+        if (timer_pending(env->timer)
+            && timer_expired(env->timer, now)) {
             /* The timer has already expired.  */
             cpu_mips_timer_expire(env);
         }