clocksource: pass clocksource to read() callback

Pass clocksource pointer to the read() callback for clocksources.  This
allows us to share the callback between multiple instances.

[hugh@veritas.com: fix powerpc build of clocksource pass clocksource mods]
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/sparc/kernel/time_64.c b/arch/sparc/kernel/time_64.c
index db310aa..5c12e79 100644
--- a/arch/sparc/kernel/time_64.c
+++ b/arch/sparc/kernel/time_64.c
@@ -814,6 +814,11 @@
 }
 EXPORT_SYMBOL(udelay);
 
+static cycle_t clocksource_tick_read(struct clocksource *cs)
+{
+	return tick_ops->get_tick();
+}
+
 void __init time_init(void)
 {
 	unsigned long freq = sparc64_init_timers();
@@ -827,7 +832,7 @@
 	clocksource_tick.mult =
 		clocksource_hz2mult(freq,
 				    clocksource_tick.shift);
-	clocksource_tick.read = tick_ops->get_tick;
+	clocksource_tick.read = clocksource_tick_read;
 
 	printk("clocksource: mult[%x] shift[%d]\n",
 	       clocksource_tick.mult, clocksource_tick.shift);