ASoC: renesas: msiof: Add note for The possibility of R/L opposite Capture

This driver is assuming MSIOF is used as Clock/Frame Consumer Mode, and
there is a case that some Codec (= Clock/Frame Provider) might output
Clock/Frame before setup MSIOF.

And, MSIOF will capture data without checking SYNC signal Hi/Low (= R/L).

This means, if MSIOF RXE bit was set as 1 in case of SYNC signal was Hi
(= R) timing, it will start capture data since next SYNC low signal (= L).
Because Linux assumes sound data is lined up as R->L->R->L->..., the data
R/L might be opposite.

The only solution in this case is start CLK/SYNC *after* MSIOF settings,
but it depends when and how Codec driver start it.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: Yusuke Goda <yusuke.goda.sx@renesas.com>
Link: https://patch.msgid.link/875xd7yutm.wl-kuninori.morimoto.gx@renesas.com


Signed-off-by: Mark Brown <broonie@kernel.org>