microblaze: timer: Use CLKSRC_OF initialization

Simplify timer initialization and prepare the driver
for moving to drivers/clocksource folder.
Also remove system-timer property from binding because
the name is too generic.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/arch/microblaze/kernel/timer.c b/arch/microblaze/kernel/timer.c
index d00a60e..6cb7f3b 100644
--- a/arch/microblaze/kernel/timer.c
+++ b/arch/microblaze/kernel/timer.c
@@ -238,24 +238,12 @@
  */
 static int timer_initialized;
 
-void __init time_init(void)
+static void __init xilinx_timer_init(struct device_node *timer)
 {
 	u32 irq;
 	u32 timer_num = 1;
-	struct device_node *timer = NULL;
 	const void *prop;
 
-	prop = of_get_property(of_chosen, "system-timer", NULL);
-	if (prop)
-		timer = of_find_node_by_phandle(be32_to_cpup(prop));
-	else
-		pr_info("No chosen timer found, using default\n");
-
-	if (!timer)
-		timer = of_find_compatible_node(NULL, NULL,
-						"xlnx,xps-timer-1.00.a");
-	BUG_ON(!timer);
-
 	timer_baseaddr = be32_to_cpup(of_get_property(timer, "reg", NULL));
 	timer_baseaddr = (unsigned long) ioremap(timer_baseaddr, PAGE_SIZE);
 	irq = irq_of_parse_and_map(timer, 0);
@@ -297,3 +285,6 @@
 	}
 	return 0;
 }
+
+CLOCKSOURCE_OF_DECLARE(xilinx_timer, "xlnx,xps-timer-1.00.a",
+		       xilinx_timer_init);