ASoC: da7218: Correct BCLK inversion for DSP DAI format mode

By default the device latches data on the falling edge of the
BCLK in DSP mode, whereas the expectation for normal BCLK is to
latch on the rising edge. This updates the driver to invert the
BCLK configuration for DSP mode, to align with expected behaviour.

Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Signed-off-by: Mark Brown <broonie@kernel.org>