ASoC: cs42l73: Fix clear wrong bits in cs42l73_set_dai_fmt

What we want is to clear BIT[5:4](PCM_MODE_MASK) and BIT[3](PCM_BIT_ORDER) bits,
but current code clears BIT[2:0].

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Brian Austin <brian.austin@cirrus.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>