drm/amdgpu: Don't halt RLC on GFX suspend

On aldebaran, RLC also controls GFXCLK. Skip halting RLC during GFX IP suspend
and keep it running till PMFW disables all DPMs.

    [  578.019986] amdgpu 0000:23:00.0: amdgpu: GPU reset begin!
    [  583.245566] amdgpu 0000:23:00.0: amdgpu: Failed to disable smu features.
    [  583.245621] amdgpu 0000:23:00.0: amdgpu: Fail to disable dpm features!
    [  583.245639] [drm:amdgpu_device_ip_suspend_phase2 [amdgpu]] *ERROR* suspend of IP block <smu> failed -62
    [  583.248504] [drm] free PSP TMR buffer

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>