drm/amdkfd: Shift sdma_engine_id and sdma_queue_id in mqd

drm/amdkfd: Shift sdma_engine_id and sdma_queue_id in mqd

FW of some new ASICs requires sdma mqd size to be not more than
128 dwords. Repurpose the last 2 reserved fields of sdma mqd for
driver internal use, so the total mqd size is no bigger than 128
dwords

Signed-off-by: Oak Zeng <ozeng@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>