[PATCH -next] drm: nouveau: fix disp.c build when NOUVEAU_BACKLIGHT is not enabled

[Randy Dunlap]

Fix build errors and warnings when
# CONFIG_DRM_NOUVEAU_BACKLIGHT is not set

../drivers/gpu/drm/nouveau/dispnv50/disp.c: In function 
‘nv50_sor_atomic_disable’:
../drivers/gpu/drm/nouveau/dispnv50/disp.c:1665:52: error: ‘struct 
nouveau_connector’ has no member named ‘backlight’
  struct nouveau_backlight *backlight = nv_connector->backlight;
                                                    ^~
../drivers/gpu/drm/nouveau/dispnv50/disp.c:1670:28: error: dereferencing 
pointer to incomplete type ‘struct nouveau_backlight’
  if (backlight && backlight->uses_dpcd) {

and then fix subsequent build warnings after the above are fixed:

../drivers/gpu/drm/nouveau/dispnv50/disp.c: In function 
‘nv50_sor_atomic_disable’:
../drivers/gpu/drm/nouveau/dispnv50/disp.c:1669:6: warning: unused variable 
‘ret’ [-Wunused-variable]
  int ret;
      ^~~
../drivers/gpu/drm/nouveau/dispnv50/disp.c:1662:22: warning: unused variable 
‘drm’ [-Wunused-variable]
  struct nouveau_drm *drm = nouveau_drm(nv_encoder->base.base.dev);
                      ^~~

Fixes: 6eca310e8924 ("drm/nouveau/kms/nv50-: Add basic DPCD backlight support 
for nouveau")
Signed-off-by: Randy Dunlap <rdun...@infradead.org>
Cc: Ben Skeggs <bske...@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Cc: nouv...@lists.freedesktop.org
Cc: Lyude Paul <ly...@redhat.com>
---
 drivers/gpu/drm/nouveau/dispnv50/disp.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- linux-next-20210714.orig/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ linux-next-20210714/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -1659,23 +1659,27 @@ 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);
+#ifdef CONFIG_DRM_NOUVEAU_BACKLIGHT
+       struct nouveau_drm *drm = nouveau_drm(nv_encoder->base.base.dev);
        struct nouveau_backlight *backlight = nv_connector->backlight;
+#endif
        struct drm_dp_aux *aux = &nv_connector->aux;
        int ret;
        u8 pwr;
 
+#ifdef CONFIG_DRM_NOUVEAU_BACKLIGHT
        if (backlight && backlight->uses_dpcd) {
                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);
+               ret = drm_dp_dpcd_readb(aux, DP_SET_POWER, &pwr);
 
                if (ret == 0) {
                        pwr &= ~DP_SET_POWER_MASK;