msm: rpc: add shutdown and restart handler for rpc

Add shutdown and restart handler for rpcrouter. The
shutdown handler take care of calling the
msm_rpcrouter_close function with a pre defined
priority. PM no longer handle rpc close in the shutdown/reboot
sequence.

CRs-fixed: 396641
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
Signed-off-by: Angshuman Sarkar <angshuman@codeaurora.org>
(cherry picked from commit 0975c60881a90c0adf36bac4739b812e34acb813)

Conflicts:

	arch/arm/mach-msm/smd_rpcrouter.c

Change-Id: I8158bfdc6ae81c9b39adbb3e4d675bc4d2aa7c6d
Signed-off-by: Gopal Goberu <ggober@codeaurora.org>