drm/amd/display: drop duplicated structure

struct gpu_info_voltage_scaling_v1_0 & gpu_info_soc_bounding_box_v1_0 is
defined in amdgpu_socbb.h

Signed-off-by: Flora Cui <flora.cui@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>