drm/amdgpu: Add query vram width in CGS query system info

powerplay need vram width to set default mclk optimization
settings(uphyst/downhyst/activity threshold)

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>