Eliminate memtrack variability in Lost RAM when ION is being used

Modify lost RAM calculation to account unmapped ION buffers as part of
kernel memory and mapped ION buffers as PSS. Because mapped ION buffers
might be accounted in memtrack HAL's reported Graphics memory, we
need to replace it with the mapped dmabufs representing mapped ION
buffers.

Bug: 174546244
Test: dumpsys meminfo
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: Ia7f5fc2ca95389a5f2ae78d4cdbf8ba3ef8e3972