msm: idle-v7 : Restore context for NR_CPUS >= 2 when PC fails

When there is a pending interrupt and the core executes WFI
instruction, the SPM would not trigger its state machine and would
bail out. The instructions after the WFI instruction will be executed.
The context calculation need to take care of getting the right context
to restore.

Change-Id: Icda4abe68503250f27b8c9b89891318beab86a7b
Signed-off-by: Praveen Chidambaram <pchidamb@codeaurora.org>