boards: frdm_mcxc242: Add uart support

Board frdm_mcxc242 does not have UART IP configured.
Add UART configuration and pin control. Set state to disabled,
as it serves as alternative to default LPUART0 or as second
uart only. Add uart to supported features in yaml.

Signed-off-by: Michal Smola <michal.smola@nxp.com>