drm/amdgpu/psp: initialize autoload_supported flag in psp_sw_init

RLC autoload is supported since from Navi10

Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Jack Xiao <Jack.Xiao@amd.com>
Reviewed-by: Le Ma <Le.Ma@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>