clocksource: timer-ti-dm.c: fix merge error

This patch fixes a merge error by maintaining omap_dm_timer_enable() as
a global function.

Signed-off-by: Eric Ruei <e-ruei1@ti.com>

drivers/clocksource/timer-ti-dm.c

@@ -215,7 +215,7 @@ static int omap_dm_timer_is_enabled(struct omap_dm_timer *timer)
 		return 0;
 }
 
-static void omap_dm_timer_enable(struct omap_dm_timer *timer)
+void omap_dm_timer_enable(struct omap_dm_timer *timer)
 {
 	int c;