drm: omapdrm: Make fbdev emulation optional

Don't compile the fbdev emulation code when fbdev emulation support is
disabled.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/gpu/drm/omapdrm/omap_fbdev.c

@@ -295,6 +295,10 @@ fini:
 	drm_fb_helper_fini(helper);
 fail:
 	kfree(fbdev);
+
+	dev_warn(dev->dev, "omap_fbdev_init failed\n");
+	/* well, limp along without an fbdev.. maybe X11 will work? */
+
 	return NULL;
 }