at91bootstrap: bump to 4.0.0
at91bootstrap: bump to 4.0.0

Signed-off-by: Eugen Hristev <0e265aa3318aee4461c7191c8b1cc156efd70e14@microchip.com>

linux4sam/meta-atmel,linux4sam/meta-atmel,linux4sam/meta-atmel,linux4sam/meta-atmel,linux4sam/meta-atmel