drm/i915: Remove dummy i915_kick_out_firmware_fb

Since

commit 44adece57e2604cec8527a499b48e4d584ab53b8
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Wed Aug 10 18:52:34 2016 +0200

    drm/fb-helper: Add a dummy remove_conflicting_framebuffers

the drm helpers take care of this for us.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161130110131.25668-1-daniel.vetter@ffwll.ch

drivers/gpu/drm/i915/i915_drv.c

@@ -643,7 +643,6 @@ out:
 	return ret;
 }
 
-#if IS_ENABLED(CONFIG_FB)
 static int i915_kick_out_firmware_fb(struct drm_i915_private *dev_priv)
 {
 	struct apertures_struct *ap;
@@ -668,12 +667,6 @@ static int i915_kick_out_firmware_fb(struct drm_i915_private *dev_priv)
 
 	return ret;
 }
-#else
-static int i915_kick_out_firmware_fb(struct drm_i915_private *dev_priv)
-{
-	return 0;
-}
-#endif
 
 #if !defined(CONFIG_VGA_CONSOLE)
 static int i915_kick_out_vgacon(struct drm_i915_private *dev_priv)