drm/amd/display: enable S/G display for for recent APUs by default

With S/G display becomes stable, enable S/G display for recent APUs
by default rather than white list.

v2: explicitly disable sg on pre-CZ chips (Alex)
v3: add parens for every clause (Alex)

Co-authored-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Yifan Zhang <yifan1.zhang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>