ASoC: sun8i-codec: add missing route for ADC

sun8i-codec misses a route from ADC to AIF1 Slot 0 ADC. Add it
to the driver to avoid adding it to every dts.

Fixes: eda85d1f ("ASoC: sun8i-codec: Add ADC support for a33")
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>