ASoC: es8328: Add support for slave mode

Currently, the function that changes the DAI format only supports master
mode. Trying to use a slave mode exits the function with -EINVAL and
leave the codec misconfigured. This commits adds support for enabling
the slave mode.

Signed-off-by: Romain Perier <romain.perier@collabora.com>
Signed-off-by: Mark Brown <broonie@kernel.org>