Add support for LSDMA v8

v2: fix wait_pio_status() per Philip's comments.

Reviewed-by: Philip Yang <philip.yang@amd.com>
Signed-off-by: Likun Gao <Likun.Gao@amd.com>
Reviewed-by: Frank Min <Frank.Min@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>