ASoC: fsl_sai: Add support to enable multiple data lines

SAI supports up to 8 Rx/Tx data lines which can be enabled
using TCE/RCE bits of TCR3/RCR3 registers.

Data lines to be enabled are read from DT fsl,dl_mask property.
By default (if no DT entry is provided) only data line 0 is enabled.

Note:
We can only enable consecutive data lines starting with data line #0.

Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>