[bl] Updating copyrights

bootloaders/zero/board_definitions.h

bootloaders/zero/board_driver_led.c

bootloaders/zero/board_driver_led.h

bootloaders/zero/board_driver_serial.c

bootloaders/zero/board_driver_serial.h

bootloaders/zero/board_driver_usb.c

bootloaders/zero/board_driver_usb.h

bootloaders/zero/board_init.c

bootloaders/zero/board_startup.c

bootloaders/zero/sam_ba_cdc.c

bootloaders/zero/sam_ba_cdc.h

bootloaders/zero/sam_ba_monitor.c

bootloaders/zero/sam_ba_monitor.h

bootloaders/zero/sam_ba_serial.c

bootloaders/zero/sam_ba_serial.h

bootloaders/zero/sam_ba_usb.c

bootloaders/zero/sam_ba_usb.h