Add a new gpu info firmware to store gpu specific configuration
data.  This allows us to store hw constants in a unified place.

v2: adjust structure and elements
v3: further restructure
Reviewed-by: Junwei Zhang <Jerry.Zhang@amd.com>
Tested-by: Junwei Zhang <Jerry.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>