drm/amd/display: Correct output color space during HW reinitialize

[Why]
Doing core_link_disable_stream or set_dpms_off when reinitializing
hardware causes issue to repro with external display connected. This is
unnecessary, blanking pixel data should be sufficient.

[How]
Call disable_pixel_data while reinitializing hardware instead of
core_link_disable_stream or set_dpms_off.

Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Michael Mityushkin <michael.mityushkin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>