rtc: at91sam9: use standard readl/writel functions instead of raw versions

rtc: at91sam9: use standard readl/writel functions instead of raw versions

Raw versions of writel and writel should not be directly used and should
be replaced by their relaxed versions (readl/writel_relaxed), which take
endianness conversion into account.

In this driver we prefer the standard readl/writel function which add the
appropriate memory barrier around the access (the performance penalty is
negligible for this kind of application).

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Acked-by: Alexandre Belloni <alexandre.belloni@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>