Having seen at least 1 42-character product_name, bump the number up to
64, and put that definition into amdgpu.h to make future adjustments
simpler.
Signed-off-by: NKent Russell <kent.russell@amd.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>