ASoC: atmel_ssc_dai: rework DAI format configuration

Rework DAI format calculation in preparation for adding more formats
later. As a side-effect this enables all CBM/CBS x CFM/CFS combinations
for supported formats. (Note: the additional modes are not tested.)

Note: this changes FSEDGE to POSITIVE for I2S CBM_CFS mode as the TXSYN
interrupt is not used anyway.
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Link: https://lore.kernel.org/r/f5949b0326fdcdca072f3ed03f77de9e207631cd.1566677788.git.mirq-linux@rere.qmqm.plSigned-off-by: Mark Brown <broonie@kernel.org>