mfd: da9063: Add support for AD silicon variant

Add register definitions for DA9063 AD (0x3) silicon variant ID
the ability to choose the silicon variant at run-time using regmap
configuration. This patch also adds RTC support for the AD silicon
changes.

It adds both BB and AD support as regmap ranges and then makes the
distinction between the two tables at run-time. This allows both AD
and BB silicon variants to be supported at the same time.

Suggested-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Opensource [Steve Twiss] <stwiss.opensource@diasemi.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>