drm/amd/display: Update correct DCN314 register header

[Why]
The register header for DCN314 is not correct.

[How]
Update correct DCN314 register header.

Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Cruise Hung <cruise.hung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>