This patch adds PM handlers to TLKD for the system suspend/resume and
system poweroff/reset cases. TLK expects all SMCs through a single
handler, which then fork out into multiple handlers depending on the
SMC. We tap into the same single entrypoint by restoring the S-EL1
context before passing the PM event via register 'x0'. On completion
of the PM event, TLK sends a completion SMC and TLKD then moves on
with the PM process.

Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>

TLK Dispatcher (tlkd) is based on the tspd and is the glue required
to run TLK as a Secure Payload with the Trusted Firmware.

Change-Id: I69e573d26d52342eb049feef773dd7d2a506f4ab
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>