timer: Return count from timer_ops.get_count

No timer drivers return an error from get_count. Instead of possibly
returning an error, just return the count directly.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/timer/ast_timer.c b/drivers/timer/ast_timer.c
index e313249..35369a4 100644
--- a/drivers/timer/ast_timer.c
+++ b/drivers/timer/ast_timer.c
@@ -51,13 +51,11 @@
 	return 0;
 }
 
-static int ast_timer_get_count(struct udevice *dev, u64 *count)
+static u64 ast_timer_get_count(struct udevice *dev)
 {
 	struct ast_timer_priv *priv = dev_get_priv(dev);
 
-	*count = AST_TMC_RELOAD_VAL - readl(&priv->tmc->status);
-
-	return 0;
+	return AST_TMC_RELOAD_VAL - readl(&priv->tmc->status);
 }
 
 static int ast_timer_ofdata_to_platdata(struct udevice *dev)