ARM: at91: add armv7m SoC detection

Add SAME70/V71/S70/V70 chip-ids to SoC detection.

Signed-off-by: Szemző András <sza@esh.hu>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>