drm: remove unused and redundant callbacks

Drivers no longer have any need for these callbacks, and there are no
users. Zap. Zap-zap-zzzap-p-pp-p.

Acked-by: Daniel Vetter <[e-mail]>
Signed-off-by: Peter Rosin <[e-mail]>
Signed-off-by: Daniel Vetter <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

include/drm/drm_crtc.h

···
 	 * drm_crtc_enable_color_mgmt(), which then supports the legacy gamma
 	 * interface through the drm_atomic_helper_legacy_gamma_set()
 	 * compatibility implementation.
-	 *
-	 * NOTE:
-	 *
-	 * Drivers that support gamma tables and also fbdev emulation through
-	 * the provided helper library need to take care to fill out the gamma
-	 * hooks for both. Currently there's a bit an unfortunate duplication
-	 * going on, which should eventually be unified to just one set of
-	 * hooks.
 	 */
 	int (*gamma_set)(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
 			 uint32_t size,

include/drm/drm_fb_helper.h

···
  */
 struct drm_fb_helper_funcs {
 	/**
-	 * @gamma_set:
-	 *
-	 * Set the given gamma LUT register on the given CRTC.
-	 *
-	 * This callback is optional.
-	 *
-	 * FIXME:
-	 *
-	 * This callback is functionally redundant with the core gamma table
-	 * support and simply exists because the fbdev hasn't yet been
-	 * refactored to use the core gamma table interfaces.
-	 */
-	void (*gamma_set)(struct drm_crtc *crtc, u16 red, u16 green,
-			  u16 blue, int regno);
-	/**
-	 * @gamma_get:
-	 *
-	 * Read the given gamma LUT register on the given CRTC, used to save the
-	 * current LUT when force-restoring the fbdev for e.g. kdbg.
-	 *
-	 * This callback is optional.
-	 *
-	 * FIXME:
-	 *
-	 * This callback is functionally redundant with the core gamma table
-	 * support and simply exists because the fbdev hasn't yet been
-	 * refactored to use the core gamma table interfaces.
-	 */
-	void (*gamma_get)(struct drm_crtc *crtc, u16 *red, u16 *green,
-			  u16 *blue, int regno);
-
-	/**
 	 * @fb_probe:
 	 *
 	 * Driver callback to allocate and initialize the fbdev info structure.

include/drm/drm_modeset_helper_vtables.h

···
 				    enum mode_set_atomic);
 
 	/**
-	 * @load_lut:
-	 *
-	 * Load a LUT prepared with the &drm_fb_helper_funcs.gamma_set vfunc.
-	 *
-	 * This callback is optional and is only used by the fbdev emulation
-	 * helpers.
-	 *
-	 * FIXME:
-	 *
-	 * This callback is functionally redundant with the core gamma table
-	 * support and simply exists because the fbdev hasn't yet been
-	 * refactored to use the core gamma table interfaces.
-	 */
-	void (*load_lut)(struct drm_crtc *crtc);
-
-	/**
 	 * @disable:
 	 *
 	 * This callback should be used to disable the CRTC. With the atomic