soc: Add Renesas SmartBond(tm) DA1469x series SoC

This adds initial support for Renesas SmartBond(tm) DA1469x series SoC.

Initailly only DA14699 is explicitly supported, however this code should
also run on other SoCs in this series since all of them support the same
core features available initially.

Signed-off-by: Andrzej Kaczmarek <andrzej.kaczmarek@codecoup.pl>
Signed-off-by: Ben Lauret <ben.lauret.wm@renesas.com>