drm/nouveau/drm: adding support for backlight control of GT525M (NVC0)

This patch adds support for the backlight control of the NVIDIA GT
525M, which identifies itself as a member of the NVC0 family.

v2. Extended to handle Kepler too

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_backlight.c

@@ -239,6 +239,9 @@ nouveau_backlight_init(struct drm_device *dev)
 		case NV_40:
 			return nv40_backlight_init(connector);
 		case NV_50:
+		case NV_C0:
+		case NV_D0:
+		case NV_E0:
 			return nv50_backlight_init(connector);
 		default:
 			break;