drm/amdgpu: Notify sbios device ready before send request

BugLink: http://bugs.launchpad.net/bugs/1764627

commit 1bced75f upstream.

it is required if a platform supports PCIe root complex
core voltage reduction. After receiving this notification,
SBIOS can apply default PCIe root complex power policy.
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

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

@@ -529,6 +529,9 @@ int amdgpu_acpi_pcie_performance_request(struct amdgpu_device *adev,
 	size_t size;
 	u32 retry = 3;
 
+	if (amdgpu_acpi_pcie_notify_device_ready(adev))
+		return -EINVAL;
+
 	/* Get the device handle */
 	handle = ACPI_HANDLE(&adev->pdev->dev);
 	if (!handle)