ARM: tegra: add common resume handling code for LP1 resuming

Add support to the Tegra CPU reset vector to detect whether the CPU is
resuming from LP1 suspend state. If it is, branch to the LP1-specific
resume code.

When Tegra enters the LP1 suspend state, the SDRAM controller is placed
into a self-refresh state. For this reason, we must place the LP1 resume
code into IRAM, so that it is accessible before SDRAM access has been
re-enabled.

Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>