drm/amdgpu: add jpeg packet defines to soc15d.h

Add new packet for vcn jpeg, including condition checks, types and packet

Signed-off-by: Boyuan Zhang <boyuan.zhang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>