haven: Align APIs and structures to account for the mem_info tag

The memory information tag is meant to be used in conjunction with
the memory notification interfaces to associate a label or tag with
a memory parcel. This memory information tag is meant to be used
for distinguishing between different memory resources that can be
transferred between Virtual Machines (VMs).

Change-Id: I6856284430ce5a78461c203904695aed25868706
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>