libmeminfo: change dmabuf_dump from soc_specific to product_specific

The vendor partition does not give dmabuf_dump enough permissions to
retrieve shared buffer information for all processes. Move it to product
partition where it can be invoked from platform's dumpstate.

Bug: 63860998

Change-Id: I73957f59943d1e49fcb59abb723aad4eeeaa4172
Signed-off-by: Erick Reyes <erickreyes@google.com>