Minidump: Add support for cpu current stack

Currently cpu's current stack are being dumped only in
panic path, which is not always helpful. So extend it to
be always dumped for any type of reset reasons.

For every task switch of cpu, update the minidump table with
latest stack. so that we can reconstruct callstack of cpu
for any type of resets.

Change-Id: Ia57a8e0473d3706efc9a88c91fb1dd60523648ad
Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org>
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>