Allow HWS to to execute multiple processes on the hardware
concurrently. The number of concurrent processes is limited by
the number of VMIDs allocated to the HWS.

A module parameter can be used for limiting this further or turn
it off altogether (mainly for debugging purposes).
Signed-off-by: NYong Zhao <yong.zhao@amd.com>
Signed-off-by: NJay Cornwall <Jay.Cornwall@amd.com>
Signed-off-by: NFelix Kuehling <Felix.Kuehling@amd.com>
Acked-by: NOded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: NOded Gabbay <oded.gabbay@gmail.com>