drivers: nrf: Fix UARTE interrupt driven operation.
drivers: nrf: Fix UARTE interrupt driven operation.

Bad order of interrupt calls made it unable to transmitt data
using interrupt driven API.

Signed-off-by: Mieszko Mierunski <0153720f373f9fb33402fd56a3b748bfb748366c@nordicsemi.no>

Vudentz/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,galak/zephyr,galak/zephyr,Vudentz/zephyr,nashif/zephyr,finikorg/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,nashif/zephyr,nashif/zephyr,ldts/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,Vudentz/zephyr,galak/zephyr,ldts/zephyr,galak/zephyr,finikorg/zephyr,ldts/zephyr,Vudentz/zephyr,nashif/zephyr