boards: frdm_k64f: Enable pullup for CAN0_RX pin
boards: frdm_k64f: Enable pullup for CAN0_RX pin

This commit enables the pullup on CAN0_RX pin (PORTB 19).
The pullup ensures that the CAN controller initializes even
without a transceiver connected.

Signed-off-by: Alexander Wachter <ce6e77dabd455f5e273537afd862be63bdedff84@student.tugraz.at>

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