Tegra186: save system suspend entry marker to TZDRAM

This patch adds support to save the system suspend entry and exit
markers to TZDRAM to help the trampoline code decide if the current
warmboot is actually an exit from System Suspend.

The Tegra186 platform handler sets the system suspend entry marker
before entering SC7 state and the trampoline flips the state back to
system resume, on exiting SC7.

Change-Id: I29d73f1693c89ebc8d19d7abb1df1e460eb5558e
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
diff --git a/plat/nvidia/tegra/include/t186/tegra186_private.h b/plat/nvidia/tegra/include/t186/tegra186_private.h
index 30b1595..9e2c02b 100644
--- a/plat/nvidia/tegra/include/t186/tegra186_private.h
+++ b/plat/nvidia/tegra/include/t186/tegra186_private.h
@@ -11,5 +11,6 @@
 uint64_t tegra186_get_cpu_reset_handler_base(void);
 uint64_t tegra186_get_cpu_reset_handler_size(void);
 uint64_t tegra186_get_smmu_ctx_offset(void);
+void tegra186_set_system_suspend_entry(void);
 
 #endif /* TEGRA186_PRIVATE_H */