boards: mimxrt595_evk,mimxrt685_evk: Instantiate WM8904

Add Flexcomm signal sharing configuration for the mimxrt595s/cm33 and
mimxrt685s/cm33 SoCs. Properly instantiate the I3C peripheral for
interfacing with the WM8904's control port. Modify pinctrl DTs of
mimxrt595_evk/mimxrt595s/cm33 and mimxrt685_evk/mimxrt685s/cm33.
Instantiate the WM8904 codec for said boards.

Signed-off-by: Hake Huang <hake.huang@oss.nxp.com>
Signed-off-by: Yves Vandervennet <yves.vandervennet@nxp.com>
Signed-off-by: Vit Stanicek <vit.stanicek@nxp.com>