drm/amd/display: Read soc_bounding_box from gpu_info (v2)

[WHY]
We don't want to expose sensitive ASIC information before ASIC release.

[HOW]
Encode the soc_bounding_box in the gpu_info FW (for Linux) and read it
at driver load.

v2: fix warning when CONFIG_DRM_AMD_DC_DCN2_0 is not set (Alex)

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>