drm/amdgpu: fix r initial values

Sriov gets suspend of IP block <dce_virtual> failed as return
value was not initialized.

v2: return 0 directly to align original code semantic before this
was broken out into a separate helper function instead of setting
initial values
Signed-off-by: Victor Zhao <Victor.Zhao@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_display.c

@@ -1412,7 +1412,7 @@ int amdgpu_display_suspend_helper(struct amdgpu_device *adev)
 			}
 		}
 	}
-	return r;
+	return 0;
 }
 
 int amdgpu_display_resume_helper(struct amdgpu_device *adev)