tools: add flash_writter for cxd56 boards
this flash writter is using the xmodem for firmware transfer
for flashing please use
tools/flash_writer.py -s -c /dev/ttyUSB0 -d -b 115200 -n nuttx.spk
Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
Approved-by: Gregory Nutt <gnutt@nuttx.org>
