Remove unnecessary save/restore of pdev->d3_delay.

The only assignments to pdev->d3_delay are in radeon_switcheroo_set_state()
and some quirks, none of which should be relevant in the
amdgpu_switcheroo_set_state() path.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NAndreas Boll <andreas.boll.dev@gmail.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>