drm/radeon/runpm: don't runtime suspend non-PX cards

Prevent runtime suspend of non-PX GPUs.  Runtime suspend is
not what we want in those cases.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

drivers/gpu/drm/radeon/radeon_drv.c

@@ -405,6 +405,9 @@ static int radeon_pmops_runtime_suspend(struct device *dev)
 	if (radeon_runtime_pm == 0)
 		return -EINVAL;
 
+	if (radeon_runtime_pm == -1 && !radeon_is_px())
+		return -EINVAL;
+
 	drm_dev->switch_power_state = DRM_SWITCH_POWER_CHANGING;
 	drm_kms_helper_poll_disable(drm_dev);
 	vga_switcheroo_set_dynamic_switch(pdev, VGA_SWITCHEROO_OFF);
@@ -427,6 +430,9 @@ static int radeon_pmops_runtime_resume(struct device *dev)
 	if (radeon_runtime_pm == 0)
 		return -EINVAL;
 
+	if (radeon_runtime_pm == -1 && !radeon_is_px())
+		return -EINVAL;
+
 	drm_dev->switch_power_state = DRM_SWITCH_POWER_CHANGING;
 
 	pci_set_power_state(pdev, PCI_D0);