Users can import device memory without specifying the target node.
DMA buf imports return a Thunk handle that's not useful for
gpu mapping calls.
Fix this by using the import node information to re-import and
map with the correct target GPU.
Also fix IPC detach calls by deregistering the Thunk handle
import immediately during attach instead of failing to do it later
on detach since Thunk handles aren't placed into ROCr allocation
map.
Finally refactor the IPC attach function for cleaner logic flow.
Change-Id: Ib2bf178110b2be98bd6917c765f724e4e613f5f2
Jonathan Kim
a3efd13a2f