drm: Protect fb_defio in drivers with CONFIG_KMS_FBDEV_EMULATION

For reasons that entirely elude me fb.h exposes all the structures,
even when it is not enabled. Except for special stuff like fb_defio.

Which means all the drivers which haven't yet switched over to the
defio support in the helpers and still roll their own, will fail
to compile when fbdev emulation is disabled. Protect just those
bits, as a gnarly reminder that conversion to the core defio helpers
would be good.

Cc: Dave Airlie <[e-mail]>
Reviewed-by: Alex Deucher <[e-mail]>
Signed-off-by: Daniel Vetter <[e-mail]>
Link: http://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/qxl/qxl_fb.c

···
 	}
 }
 
+#ifdef CONFIG_DRM_FBDEV_EMULATION
 static struct fb_deferred_io qxl_defio = {
 	.delay		= QXL_DIRTY_DELAY,
 	.deferred_io	= drm_fb_helper_deferred_io,
 };
+#endif
 
 static struct fb_ops qxlfb_ops = {
 	.owner = THIS_MODULE,
···
 		goto out_destroy_fbi;
 	}
 
+#ifdef CONFIG_DRM_FBDEV_EMULATION
 	info->fbdefio = &qxl_defio;
 	fb_deferred_io_init(info);
+#endif
 
 	qdev->fbdev_info = info;
 	qdev->fbdev_qfb = &qfbdev->qfb;

drivers/gpu/drm/udl/udl_fb.c

···
 
 	ufbdev->fb_count++;
 
+#ifdef CONFIG_DRM_FBDEV_EMULATION
 	if (fb_defio && (info->fbdefio == NULL)) {
 		/* enable defio at last moment if not disabled by client */
 
···
 		info->fbdefio = fbdefio;
 		fb_deferred_io_init(info);
 	}
+#endif
 
 	pr_notice("open /dev/fb%d user=%d fb_info=%p count=%d\n",
 		  info->node, user, info, ufbdev->fb_count);
···
 
 	ufbdev->fb_count--;
 
+#ifdef CONFIG_DRM_FBDEV_EMULATION
 	if ((ufbdev->fb_count == 0) && (info->fbdefio)) {
 		fb_deferred_io_cleanup(info);
 		kfree(info->fbdefio);
 		info->fbdefio = NULL;
 		info->fbops->fb_mmap = udl_fb_mmap;
 	}
+#endif
 
 	pr_warn("released /dev/fb%d user=%d count=%d\n",
 		info->node, user, ufbdev->fb_count);