drm/amdgpu/apci: don't call sbios request function if it's not supported

Check the supported functions mask before calling the bios
requests method.
Reviewed-by: Jim Qu <Jim.Qu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -364,7 +364,6 @@ static int amdgpu_atif_handler(struct amdgpu_device *adev,
 			       struct acpi_bus_event *event)
 {
 	struct amdgpu_atif *atif = adev->atif;
-	struct atif_sbios_requests req;
 	int count;
 
 	DRM_DEBUG_DRIVER("event, device_class = %s, type = %#x\n",
@@ -379,6 +378,9 @@ static int amdgpu_atif_handler(struct amdgpu_device *adev,
 		/* Not our event */
 		return NOTIFY_DONE;
 
+	if (atif->functions.sbios_requests) {
+		struct atif_sbios_requests req;
+
 		/* Check pending SBIOS requests */
 		count = amdgpu_atif_get_sbios_requests(atif, &req);
 
@@ -415,6 +417,7 @@ static int amdgpu_atif_handler(struct amdgpu_device *adev,
 			}
 		}
 		/* TODO: check other events */
+	}
 
 	/* We've handled the event, stop the notifier chain. The ACPI interface
 	 * overloads ACPI_VIDEO_NOTIFY_PROBE, we don't want to send that to