drm/amd/display: Revert "Add a config flag for limited_pll_vco"

drm/amd/display: Revert "Add a config flag for limited_pll_vco"

This reverts commit 82139760dcf7829ae2ca3f70442be9b53a0aff40.

[why & how]
DMUB header changes should be submitted to firmware branch first and
allowed to propagate to driver. Currently, this change breaks linux
builds so need to revert it until it's ready.

Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Ovidiu Bunea <ovidiu.bunea@amd.com>
Signed-off-by: Ivan Lipski <ivan.lipski@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>