ASoC: fsl: Update set_tdm_slot() semantics

The fsl-ssi and imx-ssi drivers use inverted semantics for the tx_mask and
rx_mask parameter of the set_tdm_slot() callback compared to rest of ASoC.
This patch updates the driver's semantics to be consistent with the rest of
ASoC, i.e. a set bit means a active slot and a cleared bit means a inactive
slot.  This will allow us to use the set_tdm_slot() API in a more generic
way.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>