tty: serial: fsl_lpuart: add earlycon for imx8ulp platform

Add earlycon support for imx8ulp platform.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/20230619080613.16522-1-sherry.sun@nxp.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>