boards: lpcxpresso55s69: switch to use the TFM_PROFILE_TYPE choice
boards: lpcxpresso55s69: switch to use the TFM_PROFILE_TYPE choice

Switch the default LPC board configuration to select the
TFM_PROFILE_TYPE_MEDIUM choice, instead of directly setting
the TFM_PROFILE variable, as this is now made hidden.

Signed-off-by: Ioannis Glaropoulos <5921cc8bab7e1d4329f52fd8f6268f9692e3de80@nordicsemi.no>

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