drm/amd/display: Drop DCN1_01 guards

[WHY]
These were only needed for bringup. They're not needed anymore.

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>