video: tegra: nvmap: track handle's mapped memory

video: tegra: nvmap: track handle's mapped memory

Added new file "maps" for nvmap heaps. In addition to data given by
existing "allocations" file, this also shows the client's virtual
mappings and total amount of handle physical memory that is actually
mapped to a client's virtual address space.

This change will help in tracking nvmap memory usage of processes.

Bug 1529015

Change-Id: I85b5c221c7a7475cbc3585b130fda6a282756662
Signed-off-by: Maneet Singh <mmaneetsingh@nvidia.com>
Reviewed-on: http://git-master/r/448503
(cherry picked from commit 1f632679174cea962406980c8201d63c163635ee)
Reviewed-on: http://git-master/r/448580
Reviewed-by: Krishna Reddy <vdumpa@nvidia.com>