drivers: can: mcan: remove unused NUM_TX_EVENT_FIFO_ELEMENTS macro
drivers: can: mcan: remove unused NUM_TX_EVENT_FIFO_ELEMENTS macro

Remove the unused NUM_TX_EVENT_FIFO_ELEMENTS helper macro. There is no
dts property for setting the TX event FIFO size.

Signed-off-by: Henrik Brix Andersen <24a3f13c22635bab658e39fc5f1e63c575328aae@vestas.com>

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