drm/tegra: Explicitly set irq_enabled

Since the Tegra DRM driver doesn't use the drm_irq_install() helper, the
irq_enabled flag needs to be set manually in order to make functionality
such as the DRM_IOCTL_WAIT_VBLANK work properly.
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

drivers/gpu/host1x/drm/drm.c

@@ -257,6 +257,13 @@ static int tegra_drm_load(struct drm_device *drm, unsigned long flags)
 	if (err < 0)
 		return err;
 
+	/*
+	 * We don't use the drm_irq_install() helpers provided by the DRM
+	 * core, so we need to set this manually in order to allow the
+	 * DRM_IOCTL_WAIT_VBLANK to operate correctly.
+	 */
+	drm->irq_enabled = 1;
+
 	err = drm_vblank_init(drm, drm->mode_config.num_crtc);
 	if (err < 0)
 		return err;