drm/amd/display: dmcu is blocking due to wrong disable ABM command

drm/amd/display: dmcu is blocking due to wrong disable ABM command

[Why]
Second screen to clone/extend mode, driver will send ABM pipe
command to DMCU. Change mode from clone/extend to second
screen only, driver send ABM level command to disable ABM but
this command will not clear ABM pipe data. At this time, change
second screen to PC screen only, driver will send first command
"ABM_LEVEL", it will turn on ABM with incorrect ABM pile so that
DMCU is blocking.

[How]
When driver try to disable ABM, change command from "ABM LEVEL"
to "ABM PIPE" so that it will clear ABM pile data.

Signed-off-by: Paul Hsieh <Paul.Hsieh@amd.com>
Reviewed-by: Charlene Liu <Charlene.Liu@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>