ARM: at91: pm: add ULP1 support for SAM9X60

Add ULP1 support for SAM9X60. In pm_suspend.S enable RC oscillator in
PMC if it is not enabled. At resume the state before suspend is
restored.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>