hrtimer: convert kernel/* to the new hrtimer apis

In order to be able to do range hrtimers we need to use accessor functions
to the "expire" member of the hrtimer struct.
This patch converts kernel/* to these accessors.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index 6522ae5..69d9cb9 100644
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -631,8 +631,7 @@
 
 	/* Setup the timer, when timeout != NULL */
 	if (unlikely(timeout)) {
-		hrtimer_start(&timeout->timer, timeout->timer.expires,
-			      HRTIMER_MODE_ABS);
+		hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS);
 		if (!hrtimer_active(&timeout->timer))
 			timeout->task = NULL;
 	}