ARM: tegra: pm: add platform suspend support

Adding suspend to RAM support for Tegra platform. There are three suspend
mode for Tegra. The difference were below.

* LP2: CPU voltage off
* LP1: CPU voltage off, DRAM in self-refresh
* LP0: CPU + Core voltage off, DRAM in self-refresh

After this patch, the LP2 suspend mode will be supported.

Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
diff --git a/arch/arm/mach-tegra/common.c b/arch/arm/mach-tegra/common.c
index c84505c..eb1f3c8 100644
--- a/arch/arm/mach-tegra/common.c
+++ b/arch/arm/mach-tegra/common.c
@@ -109,5 +109,6 @@
 
 void __init tegra_init_late(void)
 {
+	tegra_init_suspend();
 	tegra_powergate_debugfs_init();
 }