nandflash4sam-ba.tcl: update Atmel copyright.
nandflash4sam-ba.tcl: update Atmel copyright.

This script has been highly inspired from ones provided by Atmel demo
packages. Thus keep the copyright.

Signed-off-by: Gaël PORTAY <1666f60cfa201a60b0ea694168a0b6932673170a@gmail.com>

gazoo74/at91nandflash