uv_time: add parameter to uv_read_rtc()

uv_read_rtc() is referenced by read member of struct clocksource clocksource_uv.
In include/linux/clocksource.h, read of struct clocksource is declared as:
cycle_t (*read)(struct clocksource *cs)

This got introduced recently in:

   8e19608: clocksource: pass clocksource to read() callback

But arch/x86/kernel/uv_time.c was not properly converted by that pach.

This patch adds a dummy parameter (struct clocksource type) to uv_read_rtc() to
fix the incompatible reference in clocksource_uv, and add a NULL parameter in
all places where uv_read_rtc() gets called.

[ Impact: cleanup, address compiler warning ]

Signed-off-by: Coly Li <coly.li@suse.de>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Magnus Damm <damm@igel.co.jp>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hugh@veritas.com>
LKML-Reference: <49EF3614.1050806@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Dimitri Sivanich <sivanich@sgi.com>

arch/x86/kernel/uv_time.c

@@ -29,7 +29,7 @@
 
 #define RTC_NAME		"sgi_rtc"
 
-static cycle_t uv_read_rtc(void);
+static cycle_t uv_read_rtc(struct clocksource *cs);
 static int uv_rtc_next_event(unsigned long, struct clock_event_device *);
 static void uv_rtc_timer_setup(enum clock_event_mode,
 				struct clock_event_device *);
@@ -123,7 +123,7 @@ static int uv_setup_intr(int cpu, u64 expires)
 	/* Initialize comparator value */
 	uv_write_global_mmr64(pnode, UVH_INT_CMPB, expires);
 
-	return (expires < uv_read_rtc() && !uv_intr_pending(pnode));
+	return (expires < uv_read_rtc(NULL) && !uv_intr_pending(pnode));
 }
 
 /*
@@ -256,7 +256,7 @@ static int uv_rtc_unset_timer(int cpu)
 
 	spin_lock_irqsave(&head->lock, flags);
 
-	if (head->next_cpu == bcpu && uv_read_rtc() >= *t)
+	if (head->next_cpu == bcpu && uv_read_rtc(NULL) >= *t)
 		rc = 1;
 
 	*t = ULLONG_MAX;
@@ -278,7 +278,7 @@ static int uv_rtc_unset_timer(int cpu)
 /*
  * Read the RTC.
  */
-static cycle_t uv_read_rtc(void)
+static cycle_t uv_read_rtc(struct clocksource *cs)
 {
 	return (cycle_t)uv_read_local_mmr(UVH_RTC);
 }
@@ -291,7 +291,7 @@ static int uv_rtc_next_event(unsigned long delta,
 {
 	int ced_cpu = cpumask_first(ced->cpumask);
 
-	return uv_rtc_set_timer(ced_cpu, delta + uv_read_rtc());
+	return uv_rtc_set_timer(ced_cpu, delta + uv_read_rtc(NULL));
 }
 
 /*