ASoC: Intel: byt-rt5640: Set card as fully routed

Although it's not known does current version of byt-rt5640 cover all
possible variants it is better to set the fully_routed flag on in order to
disable unused codecs pins in known machines and get regression from
machines that use different routing than the default one.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>