hrtimer: convert powerpc/oprofile 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 powerpc/oprofile to these accessors.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>

arch/powerpc/oprofile/cell/spu_profiler.c

@@ -196,7 +196,7 @@ int start_spu_profiling(unsigned int cycles_reset)
 	pr_debug("timer resolution: %lu\n", TICK_NSEC);
 	kt = ktime_set(0, profiling_interval);
 	hrtimer_init(&timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
-	timer.expires = kt;
+	hrtimer_set_expires(&timer, kt);
 	timer.function = profile_spus;
 
 	/* Allocate arrays for collecting SPU PC samples */