arm/tegra: clk_get should not be fatal

The timer and rtc-timer clocks aren't gated by default, so there is no reason
to crash the system if the dummy enable call failed.
Signed-off-by: NPeter De Schrijver <pdeschrijver@nvidia.com>
Acked-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NOlof Johansson <olof@lixom.net>

arch/arm/mach-tegra/timer.c

@@ -186,16 +186,20 @@ static void __init tegra_init_timer(void)
 	int ret;
 
 	clk = clk_get_sys("timer", NULL);
-	BUG_ON(IS_ERR(clk));
-	clk_enable(clk);
+	if (IS_ERR(clk))
+		pr_warn("Unable to get timer clock\n");
+	else
+		clk_enable(clk);
 
 	/*
 	 * rtc registers are used by read_persistent_clock, keep the rtc clock
 	 * enabled
 	 */
 	clk = clk_get_sys("rtc-tegra", NULL);
-	BUG_ON(IS_ERR(clk));
-	clk_enable(clk);
+	if (IS_ERR(clk))
+		pr_warn("Unable to get rtc-tegra clock\n");
+	else
+		clk_enable(clk);
 
 #ifdef CONFIG_HAVE_ARM_TWD
 	twd_base = IO_ADDRESS(TEGRA_ARM_PERIF_BASE + 0x600);