Enable i2c6, and add a device node for the da9063 PMIC, with subnodes
for rtc and wdt.  Regulator support is not yet included.

This allows the system to be restarted when the watchdog timer times
out, or when a system restart is requested.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>