There isn't much you can do here:
> amdgpu_bo_evict_vram [amdgpu] (306.331 ms @ 74.694620)

This is evacuating the content of VRAM to RAM/disk to make sure we don't lose
screen content while suspended.

> amdgpu_fence_driver_suspend [amdgpu] (0.023 ms @ 75.000953)

Waiting for the evacuation to be completed.

> amdgpu_device_ip_suspend [amdgpu] (694.390 ms @ 75.000977)

This is hardware teardown and rather interesting and the only point we could
actually do something. Can you figure out what takes so long here?

> amdgpu_bo_evict_vram [amdgpu] (24.217 ms @ 75.695369)

Again evacuating VRAM which was locked before because the hardware was still
using it.