ARM: davinci: WARN_ON() if clk_get() fails

Currently the timer code checks if the clock pointer passed to it is
good (!IS_ERR(clk)). The new clocksource driver expects the clock to
be functional and doesn't perform any checks so emit a warning if
clk_get() fails. Apply this to all davinci platforms.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: David Lechner <david@lechnology.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>

arch/arm/mach-davinci/dm646x.c

@@ -663,6 +663,10 @@ void __init dm646x_init_time(unsigned long ref_clk_rate,
 	dm646x_psc_init(NULL, psc);
 
 	clk = clk_get(NULL, "timer0");
+	if (WARN_ON(IS_ERR(clk))) {
+		pr_err("Unable to get the timer clock\n");
+		return;
+	}
 
 	davinci_timer_init(clk);
 }