drm/amd/display: limited pll vco w/a v2

[Why/How]
The w/a will cause reboot black screen issue.

Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Jingwen Zhu <Jingwen.Zhu@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>