[PATCH] drm/nouveau/kms/nv50-: fix build failure with CONFIG_BACKLIGHT=n

[Arnd Bergmann <arnd@xxxxxxxxxx>]

From: Arnd Bergmann <arnd@xxxxxxxx>

When the backlight support is disabled, the driver fails to build:

drivers/gpu/drm/nouveau/dispnv50/disp.c: In function 'nv50_sor_atomic_disable':
drivers/gpu/drm/nouveau/dispnv50/disp.c:1665:59: error: 'struct nouveau_connector' has no member named 'backlight'
 1665 |         struct nouveau_backlight *backlight = nv_connector->backlight;
      |                                                           ^~
drivers/gpu/drm/nouveau/dispnv50/disp.c:1670:35: error: invalid use of undefined type 'struct nouveau_backlight'
 1670 |         if (backlight && backlight->uses_dpcd) {
      |                                   ^~
drivers/gpu/drm/nouveau/dispnv50/disp.c:1671:64: error: invalid use of undefined type 'struct nouveau_backlight'
 1671 |                 ret = drm_edp_backlight_disable(aux, &backlight->edp_info);
      |                                                                ^~

The patch that introduced the problem already contains some #ifdef
checks, so just add another one that makes it build again.

Fixes: 6eca310e8924 ("drm/nouveau/kms/nv50-: Add basic DPCD backlight support for nouveau")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
 drivers/gpu/drm/nouveau/dispnv50/disp.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 093e1f7163b3..fcf53e24db21 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -1659,20 +1659,23 @@ static void
 nv50_sor_atomic_disable(struct drm_encoder *encoder, struct drm_atomic_state *state)
 {
 	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
-	struct nouveau_drm *drm = nouveau_drm(nv_encoder->base.base.dev);
 	struct nouveau_crtc *nv_crtc = nouveau_crtc(nv_encoder->crtc);
 	struct nouveau_connector *nv_connector = nv50_outp_get_old_connector(state, nv_encoder);
-	struct nouveau_backlight *backlight = nv_connector->backlight;
 	struct drm_dp_aux *aux = &nv_connector->aux;
-	int ret;
 	u8 pwr;
 
+#ifdef CONFIG_DRM_NOUVEAU_BACKLIGHT
+	struct nouveau_drm *drm = nouveau_drm(nv_encoder->base.base.dev);
+	struct nouveau_backlight *backlight = nv_connector->backlight;
+
 	if (backlight && backlight->uses_dpcd) {
-		ret = drm_edp_backlight_disable(aux, &backlight->edp_info);
+		int ret = drm_edp_backlight_disable(aux, &backlight->edp_info);
+
 		if (ret < 0)
 			NV_ERROR(drm, "Failed to disable backlight on [CONNECTOR:%d:%s]: %d\n",
 				 nv_connector->base.base.id, nv_connector->base.name, ret);
 	}
+#endif
 
 	if (nv_encoder->dcb->type == DCB_OUTPUT_DP) {
 		int ret = drm_dp_dpcd_readb(aux, DP_SET_POWER, &pwr);
-- 
2.29.2