drm/i2c: tda998x: Remove duplicate NULL check

Since i2c_unregister_device() became NULL-aware we may remove duplicate
NULL check.

Cc: Russell King <linux@armlinux.org.uk>
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171031142149.32512-8-andriy.shevchenko@linux.intel.com
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

drivers/gpu/drm/i2c/tda998x_drv.c

@@ -1600,8 +1600,7 @@ fail:
 	/* if encoder_init fails, the encoder slave is never registered,
 	 * so cleanup here:
 	 */
-	if (priv->cec)
-		i2c_unregister_device(priv->cec);
+	i2c_unregister_device(priv->cec);
 	return -ENXIO;
 }