Tegra: default platform handler for the CPU_STANDBY state

This patch adds a default implementation for the platform specific
CPU standby power handler. Tegra SoCs can override this handler
with their own implementations.

Change-Id: I91e513842f194b1e2b1defa2d833bb4d9df5f06b
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
diff --git a/plat/nvidia/tegra/include/tegra_private.h b/plat/nvidia/tegra/include/tegra_private.h
index 68b4624..40aeaf8 100644
--- a/plat/nvidia/tegra/include/tegra_private.h
+++ b/plat/nvidia/tegra/include/tegra_private.h
@@ -97,6 +97,7 @@
 void tegra_pm_system_suspend_entry(void);
 void tegra_pm_system_suspend_exit(void);
 int32_t tegra_system_suspended(void);
+int32_t tegra_soc_cpu_standby(plat_local_state_t cpu_state);
 int32_t tegra_soc_pwr_domain_suspend(const psci_power_state_t *target_state);
 int32_t tegra_soc_pwr_domain_on(u_register_t mpidr);
 int32_t tegra_soc_pwr_domain_off(const psci_power_state_t *target_state);