drm: stm: remove dead code and pointless local lut storage

The redundant fb helper .load_lut is no longer used, and can not
work right without also providing the fb helpers .gamma_set and
.gamma_get thus rendering the code in this driver suspect.

Just remove the dead code.
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20170713162538.22788-14-peda@axentia.se

drivers/gpu/drm/stm/ltdc.c

@@ -362,17 +362,6 @@ static irqreturn_t ltdc_irq(int irq, void *arg)
  * DRM_CRTC
  */
 
-static void ltdc_crtc_load_lut(struct drm_crtc *crtc)
-{
-	struct ltdc_device *ldev = crtc_to_ltdc(crtc);
-	unsigned int i, lay;
-
-	for (lay = 0; lay < ldev->caps.nb_layers; lay++)
-		for (i = 0; i < 256; i++)
-			reg_write(ldev->regs, LTDC_L1CLUTWR + lay * LAY_OFS,
-				  ldev->clut[i]);
-}
-
 static void ltdc_crtc_atomic_enable(struct drm_crtc *crtc,
 				    struct drm_crtc_state *old_state)
 {
@@ -512,7 +501,6 @@ static void ltdc_crtc_atomic_flush(struct drm_crtc *crtc,
 }
 
 static const struct drm_crtc_helper_funcs ltdc_crtc_helper_funcs = {
-	.load_lut = ltdc_crtc_load_lut,
 	.mode_set_nofb = ltdc_crtc_mode_set_nofb,
 	.atomic_flush = ltdc_crtc_atomic_flush,
 	.atomic_enable = ltdc_crtc_atomic_enable,

drivers/gpu/drm/stm/ltdc.h

@@ -28,7 +28,6 @@ struct ltdc_device {
 	bool is_panel_bridge;
 	struct mutex err_lock;	/* protecting error_status */
 	struct ltdc_caps caps;
-	u32 clut[256];		/* color look up table */
 	u32 error_status;
 	u32 irq_status;
 };