rtc: at91sam9: add DT bindings documentation

Add RTT bindings documentation.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Acked-by: Johan Hovold <johan@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
1 file changed