Revert "drm/amd/display: Enable SYMCLK gating in DCCG"

This reverts commit c49e44ed.

This causes regression on DP link layer test.

Reported-by: Mark Broadworth <Mark.Broadworth@amd.com>
Acked-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>