cmake: print shields together with board
cmake: print shields together with board

Currently only BOARD is printed when running CMake.

This commit prints shields together with board, if one or more shields
are specified.

Signed-off-by: Torsten Rasmussen <a7c5b1d5a1f41fce6edfa3f7c2392ae0c59deafe@nordicsemi.no>

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