Replace the davinci_mcasp_set_pdata_from_of() function which returned a
pdata pointer with davinci_mcasp_get_config() to return an actual error
code and handle all pdata validation and private mcasp struct setup in
there.

Drop the unused ram-size-playback and sram-size-capture query from DT at
the same time.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Link: https://lore.kernel.org/r/20201106072551.689-4-peter.ujfalusi@ti.comSigned-off-by: Mark Brown <broonie@kernel.org>