watchdog_v2: Allocate memdump entries for per CPU scandump

Allocate memory in the mem dump table for per CPU scandump entry.
In case of panic we will be dumping the CPU register's using
these entries.

Change-Id: I3fc4b98d3f02cd03857aa5427006ee5d65537825
Signed-off-by: Satyajit Desai <sadesai@codeaurora.org>