the original method will change the wptr value in wb.
v2:
furthur cleanup
Signed-off-by: NEmily Deng <Emily.Deng@amd.com>
Signed-off-by: NMonk Liu <Monk.Liu@amd.com>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>