cpuidle: tegra: Disable CC6 state if LP2 unavailable

LP2 suspending could be unavailable, for example if it is disabled in a
device-tree. CC6 cpuidle state won't work in that case.
Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/cpuidle/cpuidle-tegra.c

@@ -31,6 +31,7 @@
 #include <soc/tegra/fuse.h>
 #include <soc/tegra/irq.h>
 #include <soc/tegra/pm.h>
+#include <soc/tegra/pmc.h>
 
 #include <asm/cpuidle.h>
 #include <asm/firmware.h>
@@ -337,6 +338,10 @@ static void tegra_cpuidle_setup_tegra114_c7_state(void)
 
 static int tegra_cpuidle_probe(struct platform_device *pdev)
 {
+	/* LP2 could be disabled in device-tree */
+	if (tegra_pmc_get_suspend_mode() < TEGRA_SUSPEND_LP2)
+		tegra_cpuidle_disable_state(TEGRA_CC6);
+
 	/*
 	 * Required suspend-resume functionality, which is provided by the
 	 * Tegra-arch core and PMC driver, is unavailable if PM-sleep option