Revert "drm/amd/display: Enable cur_rom_en even if cursor degamma is not enabled"

Revert "drm/amd/display: Enable cur_rom_en even if cursor degamma is not enabled"

This reverts commit 002001b092dd662ab79fcedcdd96c037cf0213d6.

The original patch introduces cursor gamma issue to multiple
Linux compositors. For this reason this commit reverts this change.

Cc: Melissa Wen <mwen@igalia.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>