Add RTC driver for Armada 38x, based on Linux' driver.
For now implement only `marvell,armada-380-rtc` compatible.
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
Cc: Pali Rohár <pali@kernel.org>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: Chris Packham <judge.packham@gmail.com>
Cc: Simon Glass <sjg@chromium.org>
Acked-by: Pali Rohár <pali@kernel.org>
