The serial-dir array gives this information so there is no need to have the
num-serializer property in DT description.
Just ignore the property in the driver the DTS files can be updated
separately without regression.
Update the documentation at the same time for davinci-mcasp
Signed-off-by: NPeter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: NJyri Sarha <jsarha@ti.com>
Signed-off-by: NMark Brown <broonie@linaro.org>