boards: up_squared_adsp: Add flasher script

Add script signing and flashing up_squared_adsp board. Can be used:

$ west flash \
<zephyr>/boards/xtensa/up_squared_adsp/tools/up_squared_adsp_flash.sh

Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
1 file changed