flash nrf52dongle

• build with dongle build target (dont forget dongle .conf file)
• nrfutil install nrf5sdk-tools
• source flash_dongle.sh

build for bl654pa

• toolchain
• nrf52840dongle_no_usb
• base config: prj.conf
• extra conf: iso.conf,internal_osc.conf
• bl654_gpio_uart.overlay