drm/amdgpu: both support PCO FP5/AM4 rlc fw

For Picasso && AM4 SOCKET board, we use picasso_rlc_am4.bin
For Picasso && FP5 SOCKET board, we use picasso_rlc.bin

Judgment method:
PCO AM4: revision >= 0xC8 && revision <= 0xCF
         or revision >= 0xD8 && revision <= 0xDF
otherwise is PCO FP5

Signed-off-by: Aaron Liu <aaron.liu@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher at amd.com>
Reviewed-by: Huang Rui <ray.huang at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>