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 <Torsten.Rasmussen@nordicsemi.no>
diff --git a/cmake/app/boilerplate.cmake b/cmake/app/boilerplate.cmake
index 93357dd..b1907c6 100644
--- a/cmake/app/boilerplate.cmake
+++ b/cmake/app/boilerplate.cmake
@@ -193,7 +193,7 @@
 # Check that BOARD has been provided, and that it has not changed.
 zephyr_check_cache(BOARD REQUIRED)
 
-message(STATUS "Board: ${BOARD}")
+set(BOARD_MESSAGE "Board: ${BOARD}")
 
 if(DEFINED ENV{ZEPHYR_BOARD_ALIASES})
   include($ENV{ZEPHYR_BOARD_ALIASES})
@@ -213,6 +213,12 @@
 # Check that SHIELD has not changed.
 zephyr_check_cache(SHIELD)
 
+if(SHIELD)
+  set(BOARD_MESSAGE "${BOARD_MESSAGE}, Shield(s): ${SHIELD}")
+endif()
+
+message(STATUS "${BOARD_MESSAGE}")
+
 # 'BOARD_ROOT' is a prioritized list of directories where boards may
 # be found. It always includes ${ZEPHYR_BASE} at the lowest priority.
 zephyr_file(APPLICATION_ROOT BOARD_ROOT)