boards: arm: nordic: nRF21540_dk_nrf52840 supports bluetooth controller
boards: arm: nordic: nRF21540_dk_nrf52840 supports bluetooth controller

The PA/LNA support for nRF21540 front-end is added in bluetooth
controller.

Signed-off-by: Ryan Chu <c7cdd57c35e5a278dc3f7d6e4b81c419226491c8@nordicsemi.no>

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