ASoC: sun4i-i2s: Register regmap and PCM before our component

So far the regmap and the dmaengine PCM are registered after our component
has been, which means that our driver isn't properly initialised by then.

Let's fix that.

Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://lore.kernel.org/r/67e303f37f141ef73ce9ed47d7f831b63c694424.1566242458.git-series.maxime.ripard@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>