drm/amdgpu: add picasso to asic_type enum

Add picasso to amd_asic_type enum and amdgpu_asic_name[].

Signed-off-by: Likun Gao <Likun.Gao@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>