ASoC: ti: davinci-i2s: Link free-run mode to SND_SOC_DAIFMT_[GATED/CONT]

McBSP has free-running mode where serial clocks continue to run during
emulation halts. This mode is always enabled by the driver.

Set free-running mode when SND_SOC_DAIFMT_CONT is selected by DAI
format, unset it when SND_SOC_DAIFMT_GATED is selected.

Signed-off-by: Bastien Curutchet <bastien.curutchet@bootlin.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@gmail.com>
Link: https://msgid.link/r/20240402071213.11671-11-bastien.curutchet@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>