boards: removed incorrect doxygen comment markers

boards/airfy-beacon/include/board.h

boards/arduino-due/include/board.h

boards/arduino-mega2560/include/board.h

boards/cc2538dk/include/board.h

boards/f4vi1/include/board.h

boards/msbiot/include/board.h

boards/openmote/include/board.h

boards/pba-d-01-kw2x/include/board.h

boards/pca10000/include/board.h

boards/pca10005/include/board.h

boards/samr21-xpro/include/board.h

boards/stm32f0discovery/include/board.h

boards/stm32f3discovery/include/board.h

boards/stm32f4discovery/include/board.h

boards/udoo/include/board.h

boards/yunjia-nrf51822/include/board.h