gpu: drm: radeon: radeon_drv: Remove unused variable 'ret'

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/radeon/radeon_drv.c: In function ‘radeon_pmops_runtime_suspend’:
 drivers/gpu/drm/radeon/radeon_drv.c:455:6: warning: variable ‘ret’ set but not used [-Wunused-but-set-variable]

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Gareth Hughes <gareth@valinux.com>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_drv.c

@@ -452,7 +452,6 @@ static int radeon_pmops_runtime_suspend(struct device *dev)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
 	struct drm_device *drm_dev = pci_get_drvdata(pdev);
-	int ret;
 
 	if (!radeon_is_px(drm_dev)) {
 		pm_runtime_forbid(dev);
@@ -462,7 +461,7 @@ static int radeon_pmops_runtime_suspend(struct device *dev)
 	drm_dev->switch_power_state = DRM_SWITCH_POWER_CHANGING;
 	drm_kms_helper_poll_disable(drm_dev);
 
-	ret = radeon_suspend_kms(drm_dev, false, false, false);
+	radeon_suspend_kms(drm_dev, false, false, false);
 	pci_save_state(pdev);
 	pci_disable_device(pdev);
 	pci_ignore_hotplug(pdev);