Import fsl-imx-audmux.h from Linux as of v5.4-rc6. The header is
unchanged since v4.18.
That would make it easier to import DT files that depend on imx-audmux
definitions from the kernel tree.
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
