rtc: sunxi: change compatibles

The Allwinner A10 compatibles were following a slightly different
compatible patterns than the rest of the SoCs for historical reasons.
Change the compatibles to match the other pattern in the RTC driver for
consistency.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>