drivers: serial: uart_mcux_lpuart: fix IRQ-driven API with ASYNC_API
drivers: serial: uart_mcux_lpuart: fix IRQ-driven API with ASYNC_API

this allows usage of the interrupt-driven API when CONFIG_UART_ASYNC_API
is enabled.

Signed-off-by: Jan Peters <a5186ea9e1ee34921f6faf65c1d013408f62e7fc@kt-elektronik.de>

zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr,galak/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr